• Cisco Unified Communications Manager 12 Install Errors on Proxmox/KVM


    The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs. qemu-kvm command: /usr/libexec/qemu-kvm -version QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard ........
  • chroot in Linux Howto Simple and Easy Guide


    chroot which stands for change root allows you to virtually operate in another operating system even though you haven't booted it. It is commonly used to deploy new distros, applications and to fix a broken Linux/Unix install or prep a new system image without having to physically boot the drive or disk. So in this example let's say we have a drive that has a Linux OS installed on /dev/sdb1 and we have mounted this partition on /mnt/sdb1 The key point is to edit the &quo........
  • VBOX VirtualBox How To Import Raw .img Disk File


    What you need to do if you have taken a dd or real raw image dump of a hard disk: VBoxManage convertdd windows2019-eval-template.img windows2019.vdi --format VDI The .img is the raw dd dump and the .vdi is the output file. --format VDIspecifies to output to .vdi format If you are in a pinch you can always use qemu-kvm binary and manually specify the .img as your disk and i........
  • LUKS Hard Drive Encryption on Linux Mint Ubuntu Debian etc how to mount encrypted hard drive


    The key thing here is to know the actual partition that is encrypted. Often in Linux Mint's installer that ends up being partition 5 or /dev/sda5 sudo cryptsetup luksOpen /dev/sda5 anynamehere You will then be prompted for your irrecoverable passphrase: Enter passphrase for /dev/sda5: If all goes well it won't say anything further. If it says ""No key available with this passphr........
  • Linux partprobe/partx cannot access last and 4th partition


    On a test machine Iwas never able to access to a newly created 4th partiton. As we can see there are dev devices for everything but the 4th partition. The normal "partprobe" or "kpartx" or kernel being told to rescan the block device didn't help (only a reboot did). fdisk -l /dev/sda Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units........
  • Linux How To Clone One System Harddrive to another remote system


    The easiest way is to use SSHand DD or a combination of netcat. SSHwill be a little slower due to encryption but is the most secure way (on two older systems the average clone speed is about 40-50MB/s). This is also OS independent as it doesn't matter what the source OS is because you are literallly cloning the drive so you retain the partition table and settings. Clone HDD using SSH and DD........
  • Ubuntu/Debian/Linux won't boot and drops to Busybox shell after cloning HDD with dd


    I don't recall having this issue in the distant past but nowadays at least Debian seems to be very picky about this. I used dd to copy one hard drive to another and tried booting it. Everything seemed fine with grub working but each time it would drop to the busybox shell. There is no particular error so this is misleading. Normally the first things you would check are to make sure your fstab is correct (that the UUID is correct)and that you've updated grub.&........
  • /usr/bin/supermin-helper exited with error status 1. To see full error messages you may need to enable debugging. See http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs at /usr/bin/virt-list-partitions line 177.


    virt-list-partitions kvmusertest.img /usr/bin/supermin-helper exited with error status 1. To see full error messages you may need to enable debugging. See http://libguestfs.org/guestfs-faq.1.html#debugging-libguestfs at /usr/bin/virt-list-partitions line 177. #solution update-guestfs-appliance........
  • Linux how to copy GPT partition table with dd


    The old MBR 512 bytes partition table is no longer valid if you are using GPT. To copy a GPT table with dd to another disk do it like so: Below sda is the source disk and destination disk is sdb (change to meet your needs). dd if=/dev/sda of=/dev/sdb bs=1536 count=1 You can also use dd to backup your partition table like normal but with the bs of 1536 dd........
  • Migrate Centos 7 from Single HDD to mdadm RAID 10 array:


    Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler! Hint do not use grub2-install! One huge caveat if you are an oldschool user or sysadmin who has avoided UEFIbooting The normal way will not work here if your Centos was using UEFI. Newer systems use it by default. The easiest way to check is to do an fdisk -l if your sy........
  • How to change reserved blocks in Linux partition


    user@box:~$ sudo tune2fs -l /dev/md99 [sudo] password for user: tune2fs 1.42.9 (4-Feb-2014) Filesystem volume name: Last mounted on: /mnt/md50 Filesystem UUID: 976a8655-2619-4587-878c-dab07f7b7652 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Fi........
  • Migrating from Linux Mint 17.2 mdadm RAID array to a new one (because I upgraded to larger drives).


    1.) Replicate the number of partitions in your new drives. gdisk /dev/sda gdisk /dev/sdb I created 3 partitions of the same same size. partition #1: +1G (/boot) partition #2: +60G (swap) partition #3: rest of it (/) #note if you are using GPT/gdisk you need to create separate a partition at least 1MB in size (in my case I would a 4th partition and mark it type ef02).........
  • mdadm how to recover from failed drive


    Remove the failed partition /dev/sde1 mdadm --manage /dev/md99 -r /dev/sde1 mdadm: hot removed /dev/sde1 from /dev/md99 Now add another drive back to replace it: # mdadm --manage /dev/md99 -a /dev/sdf1 mdadm: added /dev/sdf1 A "cat /proc/mdstat" should show it resyncing if all is well.........
  • mdadm frozen and doesn't realize array is dead/missing failed due to unplugged drives


    This was a surprising bug but I unplugged all drives for an array md127. At first it was just 1 drive and mdadm seemed to notice this. I unplugged the second drive taking the array offline but mdadm did not realize it was offline and still showed a non-existent disk as being part of it. This created problems trying to unmount it or even to stop this array with mdadm freezing. As for how to fix it I can only think of making sure you are not in a mounted path of........
  • fdisk wq causes hung process


    I created a new partition table on a newly plugged in device and it caused fdisk to hang (even force kill does not work). It also may be a bad drive or some other issue because fdisk -l hangs after the first 2 HDDs (totaly of 8 HDDs on this system): [1232879.903596] INFO: task fdisk:27176 blocked for more than 120 seconds. [1232879.903607] Tainted: P&nbs........
  • ADATA SU800 256GB 3D NAND Flash SSD Test & Review


    I keep reading these drives are slower, but they are cheap and still SSDand work very fast for my needs. As you can see the sequential read is 481-491MB/s, if I put them in MDADM RAID10 mode (normal RAID1) they should give me well over 900MB/s and with redundancy and being very cheap for what they offer. [1232206.315622] scsi 8:0:1:0: Direct-Access ATA ADATA SU800&........
  • remove gpt partition linux


    sudo fdisk /dev/sdh WARNING: GPT (GUID Partition Table) detected on '/dev/sdh'! The util fdisk doesn't support GPT. Use GNU Parted. WARNING: The size of this disk is 8.0 TB (8001563221504 bytes). DOS partition table format can not be used on drives for volumes larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID partition table format (GPT). The device presents a l........
  • mdadm change wrong device name md127 fix and solution in Linux


    md127 issue, it should be /dev/md3 per mdadm.conf Any time something is mounted as md127 it almost always means there is no entry for this mdadm array in the mdadm.conf in initramfs (which is separate from your actual /etc/mdadm.conf). cat /etc/mdadm.conf ARRAY /dev/md3 metadata=1.2 UUID=b6722845:381cc94e:7a2c5b5f:8e3b7c4f The reason for this is something strange, most Linux OS's bizarrely always keep their own copy of /etc/mdadm.con........
  • /dev/drbd0: State change failed: (-2) Need access to UpToDate data solution


    Everytime I've seen this error "/dev/drbd0: State change failed: (-2) Need access to UpToDate data" it is because DRBD has no disk: cat /proc/drbd version: 8.3.13 (api:88/proto:86-96) GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by root@sighted, 2012-10-09 12:47:51 0: cs:Connected ro:Secondary/Secondary ds:Diskless/Inconsistent A r----- ns:0 nr:0 dw:0 dr:0 al........
  • DRBD Slow Performance - 99.99 % [jbd2/drbd0-8] highiowait solution


    Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general? This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices. The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
  • mdadm zero-superblock to solve md device created on root device


    It is possible to tell mdadm to create an md device on a raw disk even though it will give you an error, it writes a superblock and this corrupts the partition table which can result in your system not booting. To fix it just zero the super-block on the offending device that you made the mistake in. Eg: /dev/sda mdadm --zero-superblock /dev/sda It is also a way of starting fresh if you wanted to create a new array.........
  • Linux How To Recover Partition Table from Kernel and Restore Centos/Debian etc..


    We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe! If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble. Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
  • 99.99 % [jbd2/drbd0-8] highiowait


    I have not found the source of this but essentially it seems like drbd and ext4 may not play well but I have to confirm still. In either case an older DRBD setup with older hard drives seems to have little to no iowait, but the main difference is the drbd partition is ext3 and not ext4. I will experiment and see if that fixes this, then we will know that DRBD and ext4 have issues.........
  • SELinux targeted policy relabel is required


    You may get this after a long time of not rebooting but especially if you have rsync'd a / partition or deployed an image to another VPS or computer, you will often have this issue. The good thing it usually just takes a reboot. Here is more info from Centos........
  • Is this partition table correct starting and ending partition on same cylinder?


    Device Boot Start End Blocks Id System /dev/sdc1 1 132 1060256+ fd Linux raid autodetect Partition 1 does not end on cylinder boundary. Partition 1 does not start........
  • Centos installing grub problems suspect gpt problem


    grub> root (hd0,0) root (hd0,0) Filesystem type is ext2fs, partition type 0xfd grub> setup (hd0) setup (hd0) But if you do: root (hd1,0) setup (hd1) it does work, I think hd0/sda had a GPT partition that was not removed properly (what I did was just dd bs=512 count=1 the partition table from another drive since the partition table should be identical). Checking if "/boot/grub/........
  • How to manually mount Linux disk image partition without using losetup


    In this case we want to mount partition #2 fdisk -lu Centos-6.6-x86_64.img You must set cylinders. You can do this from the extra functions menu. Disk Centos-6.6-x86_64.img: 0 MB, 0 bytes 255 heads, 63 sectors/track, 0 cylinders, total 0 sectors Units = sectors of 1 * 512 = 512 bytes Device Boot&nbs........
  • Windows showing wrong drive size after resizing the VPS/image or cloning howto fix


    1, Enter the command prompt Start -> cmd 2. Start diskpart diskpart 3. Find the drive that has the wrong size list volume 4. Select the volume (in this example we use volume 2) select volume 2 5. Extend the volume extend filesystem *Note the "exten........
  • mdadm real example of recovery and rebuilding of the array on Centos 6


    In this example we have 2 drives in a RAID array and /dev/sdb is the one that failed. /dev/sda1 is also the /boot partition which we tell grub to install on /dev/sdb eg install root (hd0,0) /dev/sda1 on the new drive /dev/sdb (hd1) First copy the partition table from /dev/sda to /dev/sdb dd if=/dev/sda of=/dev/sdb bs=512 count=1 Run partprobe to detect the new partition table partprobe........
  • Centos 6 how to guide convert LVM non-RAID into mdadm 1/10 RAID array live without reinstalling


    Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason. Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to? In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........
  • Centos cannot login by console or ssh session closed immediately


    In my case I could login with the initial install but I rsync'd everything over while preserving ownership and permissions to another RAID partition and booted from that.was fine before. The problem is that you are kicked out the second you login and the problem was SELINUX for some reason (perhaps it noticed something strange when it was moved to the new partition) login: pam_unix(login:session): session opened for user root by LOGIN(uid=0) login: ROOT LOG........
  • How To Install Linux Mint 17.2 on mdadm RAID with a separate boot partition


    Iwas surprised to see that Linux Mint at the latest 17.2 version still has NO mdadm installer option, and worse the installer will not be able to create a proper booting environment even when you do install it. How to setup mdadm in Linux mint LiveCD sudo su apt-get install mdadm # partition as you need and then create your mdadm devices # create your SWAP md0 mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /d........
  • grub cannot install or boot from mdadm RAID 10 array


    root (hd2,1) Filesystem type unknown, partition type 0x83 grub> root (hd2,2) root (hd2,2) Filesystem type is ext2fs, partition type 0x83 grub> setup (hd2) setup (hd2) Checking if "/boot/grub/stage1" exists... no Checking if "/grub/stage1" exists... no #weird thing about grub is that the drive you enter is considered hd0 For example when booted fu........
  • Lost connection to MySQL server during query [2013]


    This happened while trying to delete several thousand users from phpBB and basically corrupted the innoDB tables. InnoDB: Page lsn 3 881164362, low 4 bytes of lsn at page end 881164362 InnoDB: Page number (if stored to page already) 86920, InnoDB: space id (if created with >= MySQL-4.1.1 and stored already) 0 InnoDB: Page may be an index page where index id is 700 InnoDB: (index "tid_post_time" of table "phpBBdb2005"."phpbb3_p........
  • bash script linux how to do a wildcard string comparison


    if [[ "$templatesource" == *windows* ]]; then partition=/dev/sda2 fi The * before and after * windows will match this "Ihavelotsofwindowshere" Of we could have used "windows*" and anything that starts with "windows" will be matched etc...........
  • How to install grub on virtio KVM with Linux


    I messed up the bootloader by accident on a standard Centos 6.3 install because I turned the /dev/vda1 boot partition into an mdadm raid 1. This was all done correctly aside from one point Ididn't realize was an issue metadata=00.90 is the only thing that will allow you to boot (otherwise grub won't work and you won't boot). So the next step is rescue mode from a CD right? The problem you will find is that grub does not detect your hard drives, this is Ibelieve is be........
  • libguestfs tools howto guide for managing virtual machine images


    libguestfs tools howto guide for managing virtual machine images To mount a partition #mount the kvmuser102821.img image and the /dev/sda1 partition from it to the local directory "mount" guestmount -a kvmuser102821.img -m /dev/sda1 mount To list partition info on the image: virt-df image.img Filesystem........
  • drbd won't create device if previous partition is on it Command 'drbdmeta 0 v08 /dev/md160 internal create-md' terminated with exit code 40


    This is what fixed it: [root@box13 ~]# dd if=/dev/zero of=/dev/md160 bs=512 count=500 Basically you need to wipe out more than just the 512 byte partition table so 512 bytes * 500 is more than enough to make DRBD happy and think the partition is now empty. The reason this happens is because it gets confused when there is a previous partition with data on the device you are using. root@box13 ~]# d........
  • How to script fdisk in Linux bash


    (echo n; echo p; echo 1; echo 1; echo; echo wq) | fdisk /dev/sdb The above would make a new partition 1 on /dev/sdb and save the changes to disk, you can of course make changes to do almost anything in fdisk.........
  • LVM Tutorial how to create a Physical Volume (PV), Volume Group (vg), and a Logical Volume (LV) within it


    # first we need a physical volume which we use the pvcreate tool to create # I create mine on /dev/sdb3 pvcreate /dev/sdb3 dev_is_mpath: failed to get device for 8:19 Physical volume "/dev/sdb3" successfully created # pvdisplay shows the newly created volume pvdisplay "/dev/sdb3" is a new physical volume of "1.35 TiB" --- NEW Physical volume --- PV N........
  • Howto Convert Xen Image to KVM


    #count=10000 makes an image of 10000MB make sure your image is at least the same as your existing dd if=/dev/zero of=yourimage.img bs=1M count=10000 # losetup -fv newimage.raw # fdisk -cu /dev/loop0 # kpartx -a /dev/loop0 # dd if= of=/dev/mapper/loop0p1 # e2fsck -f /dev/mapper/loop0p1 # resize2fs /dev/mapper/loop0p1 # a lot of guides tell you to edit /etc/fst........
  • How to view GPT/EFI Windows Partition Table


    fdisk unfortunately can't do this and I'm not sure if there's any updated version that handles it but parted can do it. Here's an example of how to do it: parted /dev/sda print 1 17.4kB 1024MB 1024MB ntfs primary 2 1024MB 16144MB 15120MB ntfs primary /dev/sda1 would be the first partiton /dev/sda2 would be the second partition You can then just access them like any other normal partition.........
  • mdadm: Cannot open /dev/sda1: Device or resource busy


    This was caused by some weird dmraid setup which kind of takes control of drives even if they're blank/unused. 1. Check the table. dmsetup table ddf1_44656c6c202020201000006010281f0b3f5195b77cf86172: 0 3905945600 linear 8:0 0 ddf1_44656c6c202020201000006010281f0b3f5195b77cf86172p3: 0 37124096 linear 253:0 284547072 ddf1_44656c6c202020201000006010281f0b3f5195b77cf86172p2: 0 283496448 linear 253:0 1050624 ddf1_44656c6c2020202010........
  • Dell FS12-NV7 2U Server Information and Guide


    I've got one of these for testing projects from work at home and got more than I bargained for with the time I've spent on it due to the storage handing/Perc 6/i cards. My particular model came with the following: 2U Rack Mount Server with Rails 2xOpteron 2373 EE (Quad Core, there is a 6-core version that can be found at times) 16GB RAM 2 x 250GB Seagate SATA 2 x Dell Perc 6/i (horrible and a nightmare to work........
  • LSI MegaRAID Adventures, Guide and HowTo


    LSi Megaraid At first it was configured as a RAID 0, then I deleted the Virtual Disk Group. I thought both drives would be shown and detected in Linux as sda and sdb but it actually shows nothing. To make them work you have to hit Ctrl+R before the system boots (when prompted) and create a Virtual Disk Group. In my case I created each one as RAID 0 (with a single drive only) as I just wanted JBOD but there is no such option or default in these Dell Pe........
  • Samsung Galaxy Note ICS Corrupting microSDHC partition table?


    This was partitioned as a single 32GB VFAT but when I inserted it into the phone it said that it can't read it and now here is how the partition table looks. Interestingly enough the data works and reads fine from the computer still. Disk /dev/sdb1: 32.1 GB, 32085360640 bytes 64 heads, 32 sectors/track, 30598 cylinders, total 62666720 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum........
  • How to install GRUB to the MBR of a disk image.


    cat | grub --device-map=/dev/null Now pay close to the attention of the beginning. Type: "device (hd0) VPS.img" this is telling what hd0 will be to GRUB and we're telling it the disk image file "VPS.img" in the current directory is hd0, you can specify alternate paths and image names of course. GNU GRUB version 0.97 (640K lower / 3072K upper memory) [ Minimal BASH-li........
  • kvm cannot boot xen guest using lvm


    This booting error is because the Xen PV guest image uses the Xen kernel, this is not compatible with anything but a host running a Xen kernel. I did a kpartx -av virtual.img and then it created some partitions that showed up in fdisk. I mounted it and did a chroot into it and removed the xen kernel and installed a normal kernel but Xen still shows the same kernel in Grub (only the Xen one). This is strange but it seems like this Xen PV guest has some sort of hidden or........
  • mdadm: /dev/sdb1 not large enough to join array solution


    mdadm --manage /dev/md1 --add /dev/sdb1 mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: /dev/sdb1 not large enough to join array md1's first primary member /dev/sda3 has 57394 cylinders while the /dev/sdb1 has 57393 (1 less cylinder) which is why it won't work. fdisk -l /dev/sda3 Disk /dev/sda3: 47........
  • How to mount/access a single partition from dd image with Linux


    parted sdc.img GNU Parted 1.8.8 Using /home/one/sdc.img Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) unit&nb........
  • Samsung Galaxy Note Upgrade to ICS 4.0 microSDHC card not detected/dataloss after upgrading - possible solutions


    I backed up everything in the /mnt/sd_card directory thinking that some dataloss could occur for some reason but purposely left my microSDHC unbacked up thinking that "it won't touch that since it's external" and Samsung's and other manufacturers website even say this (that it won't be affected and not to worry etc). Apparently I was wrong, my microSD was "undetected" and asked to be formatted after the upgrade (there goes 3-months worth of family photos). No........
  • How to view an EFI GPT partition in Linux


    Disk /dev/sda: 320.0 GB, 320072933376 bytes 256 heads, 63 sectors/track, 38761 cylinders Units = cylinders of 16128 * 512 = 8257536 bytes Device Boot Start End Blocks Id System /dev/sda1 1 38........
  • mdadm how to add a device to an array after a failure


    This array is a RAID 1 and in this case 1 of the 2 drives failed (a WD drive and I've found them to be the weakest and most unreliable of any brand and are easily damaged/DOA when shipping them). mdadm --manage /dev/md0 --add /dev/sdb1 The above assumes the array you want to add to is /dev/md0 and the device we are adding is /dev/sdb1 *One thing to remember is to make sure the partition you are adding is the correct size for the array. You can also g........
  • Xen how to mount disk images off-line and access data


    fdisk -lu VPS.img last_lba(): I don't know how to handle files with mode 81ed You must set cylinders. You can do this from the extra functions menu. Disk VPS.img: 0 MB, 0 bytes 255 heads, 63 sectors/track, 0 cylinders, total 0 sectors Units = sectors of 1 * 512 = 512 bytes Device Boot Start End ........
  • Xen non-HVM container won't work/boot anymore


    One of my test Centos 5 containers was on a partition that filled up and it threw all sorts of errors and stopped responding but now I can't boot it again anymore. All the console shows is the Linux Penguin on the top left corner and the xm console says "usbcore: registered new driver hub" and has halted there. Centos 5 Xen container stuck/frozen won't boot on "usbcore: registered new driver hub" Another great way of troubleshooting is booting fro........
  • Linux Out of Memory OOM Object Killer Solution "Out of memory: kill process 1955 (sshd) score 81 or a child"


    I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything. I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM. I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives? Also no swap space was ever used! cat /proc/s........
  • How To Test If Your Hard Drive Is Good/Signs of dying hard drive


    I like dd, although it only reads it, usually a read test of the entire disk will uncover if your hard drive is bad in some parts. This is a good thing to do at least once a month, a lot of times bizarre program behavior, laginess and crashing/unnmounting problems etc.. are due to a failing disc and SMART won't know it or indicate a problem: We must also remember there's never a guarantee, I've found that ever since we moved to larger and more platters per drive with 1TB drives........
  • GRUB Solution to error "Error 6: Mismatched or corrupt version of stage1/stage2"


    GNU GRUB version 0.97 (640K lower / 3072K upper memory) [ Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists the possible completions of a device/filename.] grub> root (hd1,0) Filesystem type is ext2fs, partition type 0xfd grub> setup........
  • How to recover from dead DRBD partition/hard drive in two simple commands


    This assumes that you've at least created the correct partition for your DRBD already. Notice that I am "diskless", that's because either your DRBD partition doesn't exist/has been renamed (eg. sdb becomes sda when sdb dies and you reboot) or because that drive is really actually dead/gone. *If you need to permanently change the partition/device for your resource be sure to edit /etc/drbd.conf on both hosts and reload the config. (replace r0 with........
  • iPhone 3G/3GS/4 Undelete Photos/Videos Datarecovery


    I found this technique listed in many places which shows you how to use a common Linux tool "dd" to dump the raw partition of your iPhone. I give credit to this site for showing me the correct way to dd from the iPhone, I never thought to try it in the other direction:http://log.ijulien.com/post/182804914/iphone-3gs-data-recovery Requirements 1.) Jailbreak your........
  • WD EARS Advanced Format Can't be fixed?


    There's no partial WD EARS alignment fix: I had data on /dev/sda3 and /dev/sdb3 (RAID1) so I couldn't edit that one. I thought I'd be smart and try fixing the first two partitions so I set the first one starting at sector 2048 and then +8 for the second partition. This has really slowed the performance down worse than it ever was! Disk /dev/sda: 2000.4 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders, tot........
  • VirtualBox Convert Import/Boot .vmdk VMWare Hard Disk/Drive Image Won't Work


    I wanted to Import/Use a .vmdk hard disk image file from VMWare. Generally you can just "point" VirtualBox to it and use it and it will work but I found an exception. One of my Centos 4.4 x64 images wouldn't boot. I had two copies, an older one and the newer one. The older one booted as normal (once I changed the VirtualBox driver to IDE from SATA). The newer one stopped at the "GRUB loading" message no matter what I tried. As far as........
  • mdadm RAID 1 adventures


    I separated the 2 drives in the RAID 1 array. 1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated). I wonder how mdadm will handle this: usb-storage: device scan complete md: md127 stopped. md: bind md: md127: raid array is not clean -- starting background reconstruction raid1: raid set md127 active with 1 out of 2 m........
  • mdadm won't boot due to fsck error


    Nov 29 20:17:58 ubuntu kernel: [ 1157.180789] md: md1 stopped. Nov 29 20:17:58 ubuntu kernel: [ 1157.180829] md0: unknown partition table filesystem not responding/reading properly with du or rsync (this needed an fsck). [ 2571.489217] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923106 [ 2571.942299] EXT3-fs error (device md2): ext3_lookup: deleted inode referenced: 35923110 [ 2571.9568........
  • Ubuntu 10.04/GRUB2 mdadm won't boot


    Moving to RAID was a pain. What you have to do is the following from an existing install: Install mdadm Create your mdadm RAID 1 array on your spare hard drive. Start it with the missing disk. rsync the entire contents of your current / to the md partition. Here's a good way of doing it: rsync -Pha --exclude=/proc/* --exclude=/sys/* --exclude=/mnt/* /. /mnt/md2........
  • mdadm Linux Software RAID QuickStart Guide


    Create New RAID 1 Array: First setup your partitions (make sure they are exactly the same size) In my example I have sda3 and sdb3 which are 500GB in size. mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3 mdadm: array /dev/md2 started. Check Status Of The Array *Note I already have other arrays md0 and md1. You can see below that md2 is syn........
  • RAID 1 and Non-RAID Hard Drive Performance Comparison using tiobench


    Here is a RAID 1 partition (500GB Seagate & 2TB WD): Sequential Reads File Blk Num Avg Maximum Lat%&nbs........
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    This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........
  • Install Mac OS X 10.4.6 Tiger on AMD32 VMWare


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  • LUKS/cryptsetup Tutorial for Linux Hard Drive Partition Encryption


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    I was creating a RAID array and got this error: mdadm: /dev/sda1 is too small: 0K mdadm: create aborted Of course sda1 is not too small, both partitions sda1 and sdb1 are identical in size: Disk /dev/sda: 2000.3 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00000000 Device Boot Sta........
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  • Great way to backup/clone/dd your Linux partitions


    Partclone is a great tool that is basically like dd only it does not waste space, it doesn't take the whole partition, yet it does the same thing as dd, only with huge space/cost savings. Clonezilla uses partclone and is more of an integrated/easy to use suite I guess you could say. I've personally only used partclone but I wish there was an easy way to mount partclone images. I believe with Clonezilla you can do that, so I will probably give it a shot next time.........
  • Debian 5.04 RAID 1 mdadm boot problem GRUB error


    I successfully created a single RAID 1 partition which includes /boot inside it and my root directory through the Debian installer. It said GRUB installed successfully but when I try booting the OS it seems GRUB can't read anything. When trying to boot from GRUB GRUB Loading stage 1.5. GRUB loading, please wait... Error 2 I get "Error 2" when trying to boot Debian. I also notice from a LiveCD that........
  • Centos 5.5 RAID 1 boot issue


    I installed 5.5 with a 300GB RAID 1 partition (boot is also on this partition). It booted up fine the first few times until after I used a Live CD and accessed the array, and it became named /dev/md127 for some reason. Now whenI boot into CentOS I get a kernel panic and different errors, once I got "invalid superblock", even though the array is fine (it didn't happen again, probably because I was sure to dismount and stop the mdadm array properly). Here's what........
  • Asus Eee PC 1000HE Crashed/Need To Recover/Restore Windows? Easy Solution is Hitting F9


    I'm not a fan of Asus and won't be buying another because of having to fight Asus over a bogus warranty denial (it's a long story but they only replied about how to RMA my unit weeks later on the EXACT day the warranty expired). Anyway, it's just a matter of hitting F9 to do this, there's no need to worry about booting from USB or CD (unless of course you want a different OS eg. Windows XP Pro, Vista/7, or a flavor of Linux or Unix). Also remember that you need to fully/properl........
  • rsync my favorite/best/optimal default switches and options


    Not sure what rsync switches/options to use? rsync -PDrphogtl The short version would be: rsync -Pha I think these are really common sense options to use and probaby should be the default. Explanation of rsync switches P = display the progress D = hybrid of --specials and --devices so all special and device files will be copied as well. r = recursive (otherwise rsync won't copy files deeper than........
  • Linux AHCI Hotswap Tips - Remember To Reread The Partition Table WITHOUT rebooting


    From the package "parted" you can use the command "partprobe" to re-read the partition table. I really hate rebooting, and that's what Iloved to hear about AHCI motherboards, that they allow hotswap so you don't have to reboot. But that's only as good as the OS, if the OS does not reload the partition table you won't be able to do anything with that new drive you attached without rebooting. Yes, even without re-reading the partiton table Linux will........
  • Convert HDD/Hard Drive Partition(s) into non-RAID into RAID 1 using existing data without data loss and without reformatting.


    Before we start I take no responsibility for this, you should have a backup and if you make a mistake during this process you could wipe out all of your data. So backup somewhere else before starting this as a precaution, or make sure it's data you could afford to lose. The RAID 1 Setup (Hardware Wise) I've already setup my 2 x 1TB (Seagate) drives with identical partitions, make sure your new hard drive (the empty one) is setup like your curr........
  • Linux EXT3 16GB-17GB maximum filesize issue solved/how to fix


    I have no idea why but mkfs.ext3 defaults to a patheticlly small blocksize of 1024 bytes/1KB (kilobyte). That means the maximum filesize is ONLY 16GB! With 2KB/2048 bytes you get a 256 GB maximum filesize, and with 4KB/4096 bytes you get 2TB! I finally noticed/paid attention to this after realizing that with rsync and scp that no file larger than 17GB could be transferred. I then realized it must be a file size limit on the partition. Here is what tune2fs tol........
  • Picking an FTPD (vsftpd) Server in Linux Centos/Debian


    I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * rpmforge: ftp-stud.fht-esslingen.de * base: mirrors.netdna.com * updates: updates.interworx.info * addons: yum.singlehop.com * extras: mirrors.netdna.com rpmforge........
  • ntfs-3g Error/Fix/Solution - Unexpected sectors per cluster value (127). Failed to mount '/dev/sda1': Invalid argument The device '/dev/sda1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a


    ./ntfs-3g /dev/sda1 /mnt -o force Unexpected sectors per cluster value (127). Failed to mount '/dev/sda1': Invalid argument The device '/dev/sda1' doesn't seem to have a valid NTFS. Maybe the wrong device is used? Or the whole disk instead of a partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around? This is happening on a system I've come across an HP 6930P running Windows XP Professional. The partition appears to be very norm........
  • Clone any OS partition perfectly


    Clone any OS partition perfectlyIn one box I needed to copy the boot partition to another disk while retaining the MBR and other data. I simply ran this command: [code:1:1b1ff110ca]dd if=/dev/hda1 of=/dev/hdb1[/code:1:1b1ff110ca] [b:1b1ff110ca]if[/b:1b1ff110ca] = source patition [b:1b1ff110ca]of[/b:1b1ff110ca] = destination partition Here's an interesting article on it http://www.rajeevnet.com/hacks_hints/os_cl........
  • GRUB Boot FreeBSD


    GRUB Boot FreeBSD[code:1:a7050277b7]title FreeBSD 6.0 root (hd0,2,a) kernel /boot/loader[/code:1:a7050277b7] Just insert the above code into GRUB's [b:a7050277b7]menu.lst[/b:a7050277b7] and make sure you set the root path correctly. [quote:a7050277b7]Let's quickly explain what the root (hd0,2,a) means: *hd0 stands for the primary master drive *2 stands for partition 3 *a stands for the........
  • FreeBSD Desktop OSs


    FreeBSD Desktop OSsI would probably choose these over Linux. In many ways these are probably more stable and just as easy to use as any Linux distros but the benefit of stable, updated and secure packages! PC-BSD - http://www.pcbsd.org DesktopBSD - http://www.desktopbsd.net/index.php?id=37 Personally PC-BSD is Beta at this point and is not easy if you are installing it on a non-primary partition. I have not used Deskt........
  • Mounting NTFS in Unix


    Mounting NTFS in UnixJust a quick tutorial to mount your NTFS volumes in Unix (FreeBSD/Linux) [quote:4a9de7bf80]mount -t ntfs -o umask=0 /dev/your_partition /mnt/your_mount_point[/quote:4a9de7bf80] [b:4a9de7bf80]-o umask=0[/b:4a9de7bf80] is to ensure all users can access the mounted partition (otherwise don't use it and only root can access the mounted partition) [b:4a9de7bf80]-t ntfs[/b:4a9de7bf80] is simple because it just lets mount kno........
  • MySQL "Got error 28 from storage engine"


    I've gotten this error enough to bother posting about it, because I've come across so many servers where this happens, so what could "Error 28" possibly mean? Is your database corrupt, or is this a sign of a RAID failure/corruption or even worse, bad blocks on a clients system who has no RAID and never took backups? No, check your free blocks, it simply means you have no space. This was the result of a script that was overzealous and backed up the entire database........
  • How to Track Down/Find Cause of Linux high disk iowait/wa


    top - 09:34:12 up 2 days, 20:57, 2 users, load average: 1.83, 1.99, 2.03 Tasks: 59 total, 2 running, 57 sleeping, 0 stopped, 0 zombie Cpu(s): 0.3%us, 0.0%sy, 0.0%ni, 0.0%id, 99.7%wa, 0.0%hi, 0.0%si, 0.0%st That 99.7% wa is iowait, it means the server is waiting for a process to complete an IOoperation or in plain English, there is a delay in........
  • GRUB "Error 2: Bad file or directory type" 0.97 won


    You can see the problem below, GRUB recognizes my hard drive and sees the partitions but cannot access them. This is from the GRUB boot disc I'm using. What happened is that I had some power issues causing this system's power to be interrupted several times and basically an on/off on/off situation. The system won't boot, I just get a flashing cursor and no message or error from GRUB. Obviously the problem is that my MBR seems corrupt or some other issue. My........
  • Clustered/Distributed Network Filesystems, Which Ones live up to the hype?


    I've tried to find a good sensible solution to cluster with and each technology has it's pros and cons and there is no perfect solution and I've found a lot of "exaggerations" in the applications, benefits and performance of these different filesystems. DRBD I first started off with DRBD and Ihave to say it does live up to the hype, is quite reliable (although it can be annoying to match up the kernel module and user applications since they must match and whe........
  • Tyan S2735-8M Maximum Hard Drive Limit/Not Working/Doesn't work with 1TB 1000GB hard drives


    Inever saved any of the logs, but basically no matter what OS (Linux)I used, I could not get my 1000GB hard drive to work (Seagate SATA). The BIOS recognizes the drive and fdisk -l shows the hard drive as it should. The tricky thing is that different OS's will give you different results, but don't be fooled. You can't use these larger drives for long. Iwas getting all kinds of seek/IOerrors and also messages that the port could not be read.........
  • Using a Mac OSX DMG Image in Windows and Converting to Standard ISO Format use dmg2iso


    The dmg format is silly and annoying to work with, why couldn't Apple stick with the .iso standard? Anyway, there's an excellent Linux and Windows based tool to convert it back to a normal .iso Image called dmg2iso I'll only cover theLinux version although the Windows pre-built binary works the same way. Download dmg2iso here for free (from the author's website) It's just silly and doesn't make sense that Ubuntu doe........
  • resume: could not stat the resume device file


    resume: could not stat the resume device file I got that after migrating to a different physical hard drive, it wanted to resume from a swap partition that no longer exists. This is actually controlled by "uswsusp.conf" in /etc Just edit it and remove the device or change it to the correct new swap file.........
  • OCFS2 crash


    When trying to even cd or ls the mounted OCFS2 partition it crashes. Ithink this is a combination of VMWare Server's problem and the way I mounted and symlinked to it. More than anything this shows the problem and lack of forsight with VMWare, but also that OCFS2 is easily crashed if you do strange things. Output of /var/log/messages for OCFS2 Apr 10 15:57:45 localhost kernel: [84331.691258] Modules linked in: vmnet vmci vmmon ocfs2_stac........
  • Configuring OCFS2 Clustered File System on Debian Based Linux including Ubuntu and Kubuntu


    There's a lot of information and guides on OCFS2 for RHELand Centos Linux but the package setup and configuration is slightly different and this has thrown some people off. Installing OC2FS You should install the following packages to get started: apt-get install ocfs2-tools ocfs2console Configure OC2FS In RHEL/Centos the main configuration file is located in /etc/sysconfig/o2cb However in Debian based Linux it is located........
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