• Debian Ubuntu Mint Howto Create Bridge (br0)


    Having a network bridge allows you to bridge traffic under multiple devices so they can talk natively without using any special routing, iptables/firewall or other trickery. To create your bridge you need the bridge-utils package for brctl and if you want to do things like bridge VMs that run on a tap device you will need the uml-utilities which provides "tunctl". Install the utilities to make our bridge sudo apt-get install........
  • Debian Ubuntu and Linux Mint Broken Kernel After Date - New Extra Module Naming Convention


    This is something I've seen some run into. Take an old install of Linux Mint 18.1 ii linux-image-4.4.0-53-generic 4.4.0-53.74 amd64 Linux kernel image for version 4.4.0 on 64 bit x86 SMP i........
  • Linux delete unused tap devices automatically


    This will find all tap devices and try deleting all of them. Of course don't run this if there is a chance an unused tap device is necessary and would not be created by the script ro application using it. for tap in `ifconfig -a|grep tap[0-255]|awk '{print $1}'`; do tunctl -d $tap done........
  • 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........
  • Cisco Router Setup Guide and Tutorial Howto With Commands and Examples


    In most of the Cisco router IOS I find the ports like ge0/0 ge0/1 and ge0/2 or whatever your ports are down. They will not even give you a link light. So one of the first tasks should be getting the port you are working with up. In my case the first goal is often connectivity with the LAN and WAN. LAN = your local area network (eg. in the office/home ) WAN= your ISP/public internet (eg. fiber/cable/dsl/ethernet). In these examples I as........
  • proxmox vm networking breaks when you restart your network on the hostnode


    Idid a systemctl restart networking and it broke Proxmox VM connectivity! #proxmox is the problem after restarting the network the tap devices go to disabled state [2230884.919905] vmbr0: port 7(tap118i0) entered disabled state [2230884.948864] vmbr0: port 8(tap122i0) entered disabled state [2230884.972748] vmbr0: port 6(tap119i0) entered disabled state [2230885.004745] vmbr0: port 5(tap117i0) entered disabled state [2230885.03673........
  • How to use nmap locate other machines/computers/servers on your network using nmap


    A lot of people think arp wil do it but the arp table will only show devices you have communicated with. Using nmap is a quick and simple way to scan a range to find a machine you may not know the IP for: eg: nmap -sP 10.1.5.0/24 Just change the above to your subnet........
  • 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........
  • iSCSI on Centos 7 Configuration and Setup Guide for Initiator and Target


    initiator = client target = server These are the first concepts you should understand which is that in iscsi essentially the "initiator" is the client and the "target" is the server. iSCSI is derived from the old fashioned SCSI that us oldtimers grew to love. The "i" stands for Internet and the SCSI stands for "Small Computers Systems Interface" (SCSI). iSCSI Target (Server)Setup targetcli is the pac........
  • How Does Cisco CUCM (Cisco Unified Communication Manager) Work?


    Cisco's CUCM (Cisco Unified Communication Manager) is a system that combines voice, video, data and mobile products into a single unified management suite. At its core, the CUCMis like a "Super PBX" that controls the flow of all communications through an organization even single or multiple site deployments. Cisco's CUCMmakes communication more effective and simple through centralized management and unification of communications resources.........
  • Linux Mint Black Screen after boot no graphics solution


    This is not the normal "black screen"issue and I was shocked to eventually find out why. The normal advice of reconfiguring Xorg didn't work. Even booting into "Recovery Mode" did not help. Here is the short end of the stick that fixed it: sudo apt-get install mdm mate-desktop-environment Yes you got it right, mdm and the mate-desktop-environment / gnome were somehow uninstalled. This must be whe........
  • Linux input/output error invalid program cannot read data on some CD-Rs and DVD-Rs on ASUS BW-16D1HT


    I've never seen this before in all of my years. Ihave some very old CDs and DVDs 12-15 years old that seem not to work in this BD-R/DVD-R/CD-R Asus drive. The discs are fine actually and ironically they even work fine on a normal LG USB based BD-R drive! Here are the errors in Linux: [2914936.884924] attempt to access beyond end of device [2914936.884927] loop1: rw=0, want=730424, limit=688384 [2914954.556873] attempt to........
  • Linux how to view video card make and exact model


    Normally lspci will show you just like this and would suggest they are exactly the same card: 1a:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/580] (rev e7) 1c:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/580] (rev e7) lspci -vnn is the answer As we can see one is a Gigabyte and the other is an MSI card. Wha........
  • How to Update Linux /usr/share/misc/pci.ids


    This works with lspci and if it's outdated may not give you the exact manufacturer and device model. For example take these 3 different RX 580's: 1a:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 67df (rev e7) 1b:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 67df (rev e7) 1d:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 67df (rev e7) You ca........
  • pcimodules and lspci not working alternative solution


    pcimodules no longer works it produces nothing probably because the format of /sys/bus/pci is different. lspci -k doesn't work on older lspci versions. pciutils can be compiled but it won't work if you have an old system and compile on a newer glibc. iteriate through /sys/bus/pci/devices/*/modalias cat /sys/bus/pci/devices/*/modalias pci:v00008086d00001237sv00000000sd00000000bc06sc00i00 pci:v00008086d00007000sv0000000........
  • Linux Mint USB Kernel Tainted and Locked Port/Dev File


    Essentially a program I was running for mining did not terminate properly with Ctrl+C it is listed as defunct and cannot be killed, kernel is tainted and normal tricks to disable the port are impossible the dev and sys entries for the device cannot be browsed or interacted with in any form without a lockup of the request. The only solution is to reboot due to the kernel taint as far as I can find so far. [1130246.811056] INFO: task minerd:21861 blocked for more th........
  • OpenVZ error : Container start failed (try to check kernel messages, e.g. "dmesg | tail") Locked by: pid 166638, cmdline vzctl start 888171


    This container won't start after exhausting its memory. There are no relevant or helpful messages in dmesg or vzctl.log as well. Standard troubleshooting such as disabling PPP etc has not helped. 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Locked by: pid 166029, cmdline vzctl start 888171 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container already locked 2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container was stopped 2017-07........
  • USB 3.0 External HDD Enclosure Seagate UAS problems - [sdd] tag#1 CDB: Write(16) 8a 00 00 00 00 01 70 04 08 68 00 00 00 08 00 00


    This is a 8TB Seagate external USB 3.0 device apparently newer kernels use a module called "UAS" instead of "USB Storage" which causes issues as a lot of devices are not properly supported in UAS mode by the kernel driver. The solution some say is to disable UAS specifically for your USB device but I'd rather just disable UAS altogether. Solution blacklist UAS: *do not do this it does not work and just causes your USB 3.0........
  • USB 3.0 PCI x1 Card Review VIA VL805 on Linux Review and Experience


    This is a VIA made VL805 USB 3.0 Chipset with 4-ports and MOLEX powered. First of all this unit was cheap at about only 9 USD with fast shipping. My biggest concern was if this was a quality unit and would it really give you full USB 3.0 speeds (some people reported with similar cards that for some weird r........
  • USB Device/MP3 Player not working properly and can't browse the device filesystem? Check the cable twice and again!


    Here is a simple MP3 player and now there's a reason to understand why the supplied cable has some kind of capacitor and is very short. These devices can be VERY finicky and any voltage fluctuation or difference is enough to cause issues. Take for example the error messages from Linux Mint: [804829.895414] usb 1-1: USB disconnect, device number 11 [806961.109030] usb 1-1: new high-speed USB device number 12 using xhci_hcd........
  • Apache SSL very slow response with Firefox Freezes/Loads Very slow when checking self-signed SSL certificate


    I was sure this was a Centos bug with OpenSSL, Apache, MySQL or even PHP. I tried everything but nothing helped. One clue is that if you check the Apache logs you will see nothing in the access logs until minutes later (this means Firefox has not even passed your request to the remote Apache/htttpd server). When even accepting the invalid certificate message that would show up minutes later when trying to "View the Certificate" Firefox would freeze. This bu........
  • What happens when you unplug 1 or more devices from an mdadm RAID array to simulate a failure in Linux Ubuntu/Centos/Debian?


    In short the two drives in the array were /dev/sdd and /dev/sde. The kernel sees they were unplugged and have gone down as you can see below. mdadm caught the first one being unplugged /dev/sde and disabled the missing drive. However when the final drive that was part of the array is unplugged it didn't notice at all. Instead it complains about an IO error later for drives that the kernel knows do not exist anymore. [45817.162728] ata4: exception........
  • 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 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........
  • mdadm kernel panic if trying to change --layout on a RAID10


    It is already known this is not possible mdadm --create /dev/md3 --level 10 --layout=f2 --raid-devices=2 /dev/sdc1 /dev/sdd1 mdadm: /dev/sdc1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 mdadm: /dev/sdd1 appears to be part of a raid array: level=raid10 devices=2 ctime=Sat Dec 24 18:44:29 2016 Continue creating ar........
  • 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........
  • OpenVZ Migration Hostnode Containers from Centos 5 to Centos 6


    migrating from an old OpenVZ (Centos 5) to new OpenVZ (Centos 6) Also if migrating from 32-bit HN to 64-bit your RAM will probably be much bigger than it should be! 16x bigger eg. 32bit HN: total used free shared buffers cached Mem:&nb........
  • Nvidia Linux Card not working due to LSI 9200/SAS2008 IRQ conflict


    At first my BIOS said the card may not work right because there is no more option ROM space. I disabled the Option ROM for both LSI 1068 and 2008 chipsets, Network Boot ROM and most other PCI slots, Serial Port, etc... and the message went away but the card still does not work properly. But it still cannot initialize the card properly(does not work): [ 33.943272] NVRM: This PCI I/O region assigned to your NVIDIA device is invalid:........
  • Linksys E2500 DD-WRT Upgrade Instructions and Enabling 5ghz with Tomato Firmware


    1.) Flash directly to this file: http://tomato.groov.pl/download/K26RT-N/build5x-132-EN/Linksys%20E-series/tomato-E2500-NVRAM60K-1.28.RT-N5x-MIPSR2-132-Max.zip *I was never able to get the larger "Mega" file to work, at least not initially so I recommend the file above. To enable 5ghz I had to do the "Clear NVRAM" Option before it was shown. 2.) Or if you don't need 5ghz (most devices do not support it and cannot........
  • Errors were found while checking the disk drive for /.


    Iwill start by saying I think I know what caused this boot-time error on Linux Mint but should also apply to Debian and Ubuntu. I changed my BIOS time to several hours in the past to match the current time, but this caused Linux to think there were incorrect filesystem times. The problem is that it seems when you hit this I am not sure what is happening, it doesn't seem to be doing fsck and hangs without prompting the user. What I have found is that........
  • 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........
  • 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........
  • ONVIF Linux Security Camera Setup


    First of all this seems to apply to many ONVIF devices Hard coded IP: 192.168.1.10 (yes not kidding no DHCP!) 00:12:12:9C:C2:00 To view RTSP stream use VLC, or openRTSP or other RTSP capable software: rtsp://192.168.1.10/user=admin_password=tlJwpbo6_channel=1_stream=0.sdp user: admin password: blank http://ip/Login.htm Uses Quicktime and is a poor quality picture and slow Cannot change pass........
  • mdadm create raid10 array with only 2 drives


    mdadm --create /dev/md1 --level 10 --raid-devices=2 /dev/sdb2 /dev/sdc2 --layout=f2 --metadata=0.90 Note that layout=f2 or layout=n2 is very important as without it you'll get a complaint like this: mdadm --create /dev/md0 --level 10 --raid-devices /dev/sdb1 /dev/sdc1 missing missing mdadm: invalid number of raid devices: /dev/sdb1 It is basically more like a prop........
  • Dell CS24-NV7 lspci dmidecode info


    0000:00:00.0 RAM memory: NVIDIA Corporation MCP55 Memory Controller (rev a2) 0000:00:01.0 ISA bridge: NVIDIA Corporation MCP55 LPC Bridge (rev a3) 0000:00:01.1 SMBus: NVIDIA Corporation MCP55 SMBus (rev a3) 0000:00:02.0 USB controller: NVIDIA Corporation MCP55 USB Controller (rev a1) 0000:00:02.1 USB controller: NVIDIA Corporation MCP55 USB Controller (rev a2) 0000:00:05.0 IDE interface: NVIDIA Corporation MCP55 SATA Controller (rev a3) 0000:00:05.1 I........
  • VPN Account Buyers Guide and General Info


    What does VPN stand for? VPN stands for Virtual Private Network and is a secure way of connecting networks and devices. In the context we're talking about it will usually be a client-server solution and not connecting whole networks or businesses. The assumption is that most people reading this are trying to secure their internet connection, privacy and hide or change their IPaddress. Why use a VPN? There are many........
  • Vbox/Virtualbox devices grayed out for non-root user solution


    It is a permissions issue that is hard to fix. All but one USB device is greyed out. I am already a member of "vboxusers" I have already enabled and disabled USB support for the guest. I have already reinstalled the latest VBOx guest editions If running as root it all works fine Changing........
  • 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........
  • What a hdd hard drive and mdadm RAID array failure looks like in Linux


    [3805108.257042] sd 0:0:0:0: [sda] 1953525168 512-byte hardware sectors: (1.00 TB/931 GiB) [3805108.257052] sd 0:0:0:0: [sda] Write Protect is off [3805108.257054] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [3805108.257066] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [3805108.257083] sd 0:0:0:0: [sda] 1953525168 512-byte hardware sectors: (1.00 TB/931 GiB) [3805108.257090] sd 0:0:0:0: [sda] Write Protect is off........
  • strange kernel dmesg errors


    Sep 26 16:56:21 box kernel: 00 00 00 00 00 00 00 00 Sep 26 16:56:21 box kernel: [37007.155690] d_alias libdl-2.12.so d_count=9 d_flags=8 Sep 26 16:56:21 box kernel: [37007.155697] 09 00 00 00 08 00 00 00 9f 05 9f 05 00 00 00 00 c0 71 1d 18 04 88 ff ff 00 00 00 00 00 00 00 00 a0 7e 48 00 00 c9 ff ff 78 a9 21 18 04 88 ff ff 3a 7b fa 4e 0d 00 00 00 98 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de f8........
  • mdadm how to add additional RAID 1 drives


    This is a great way to upgrade your RAID array or move it/copy it to a new set of hard drives. Eg. you have a current RAID 1 array on older/slower drives. Just add at least 1 of the new drives to the array, update grub/install it and then boot into it. Then you have a transparent data migration that is fully synchronized. mdadm --grow /dev/md126 --raid-devices 3 md127 : active raid1 sdc1........
  • 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........
  • pxe-32 tftp open timeout


    pxe-32 tftp open timeout The solution was to enable tftp in xinetd with "chkconfig tftp on". See the troubleshooting below: chkconfig --list NetworkManager 0:off 1:off 2:off 3:off 4:off 5:off 6:off acpid 0:off&n........
  • Antec ECO450C Crashing


    Crashing with a RAID 1 array and when burning a CD. Screen goes blank (no video signal) and system stops responding during heavier loads. Is this a defective power supply or is it possible I have too many devices connected to the same rail? How can I verify/troubleshoot this?........
  • mdadm enable bitmap to speed up rebuilds


    Have you ever unplugged the wrong drive and then had to rebuild the entire array? It may not be a big deal in some ways but it does make your system vulnerable until the rebuild is done. Many distros often enable the "bitmap" feature and this basically keeps track of what parts need to be resynced in the case of a temporary removal of a drive from the array, this way it only needs to sync what has changed. To enable bitmap to speed up rebuilds and sync........
  • Ubuntu/Linux disable extra Mouse Buttons Microsoft Comfort Mouse 4500


    I find it very annoying that this mouse has buttons on the side where you grip it and the left one goes back in the browser and the right one goes forward. Imagine if you're filling out a form and hit it, most forms/websites have no protection against it. Source: http://ubuntuforums.org/showthread.php?t=2065400 Here's how I fixed it with xinput, it's too bad there's no good standard GUI to........
  • mdadm create RAID 1 array example


    mdadm --create /dev/md2 --level=1 --raid-devices=2 /dev/sda3 /dev/sdb3 cat /proc/mdstat Personalities : [raid1] md2 : active raid1 sdb3[1] sda3[0] 1363020736 blocks super 1.2 [2/2] [UU] [=>...................] resync = 8.3% (113597440/1363020736) finish=276.2min speed=75366K/sec ........
  • mdadm recover from dead drive


    mdadm --manage /dev/md3 --add /dev/sda1 cat /proc/mdstat Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md0 : inactive sdd2[1] sdd1[2](S) 31270272 blocks md3 : active raid1 sda1[2] sdb1[1] sdc1[3](F) 943730240 blocks [2/1] [_U] [>....................]........
  • Nearly 100% CPU Usage from processes called dma0chan0 dma0chan1 dma0chan2 dma0chan3


    Inever started these processes but they are from a custom based bootable Linux I've made and I've never seen this behavior on other machines or even with the same machine using different kernels. These processes seemed to spawn on their own and I have no idea why and even worse why the CPU usage is so high? Here's the output from top: 907 extaudit 30 10 0 0 0 R 90.7 0.0........
  • Linux Ubuntu/Debian ATI 9902 No Sound Solution on HP G6 Pavilion Laptop


    00:14.2 Audio device: Advanced Micro Devices [AMD] Hudson Azalia Controller (rev 01) 00:01.1 Audio device: Advanced Micro Devices [AMD] nee ATI Device 9902 Backup your also.conf file cp /usr/share/alsa/alsa.conf /usr/share/alsa/alsa.conf.bk Change all instances of "card 0" to "card 1" (no need to manually do it, this command below does it all instantly and without fail or error:........
  • 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........
  • Debian UUID not working


    Neither the blkid or the UUID internal to mdadm work to automount for some reason in Debian partprobe doesn't work but was a good suggestion from: http://pato.dudits.net/2008/11/03/special-device-uuidxxxxxxxxxxxxxxxx-does-not-exist-especially-with-lvm mount: special device /dev/disk/by-uuid/431b9b96-29e8f298-e89bd504-7065bddd does not exist mdadm -D /dev/md_d12 mdadm: metadata format 00.90 unknown, ignored. /dev/md_d12: &nb........
  • Skype Linux/Ubuntu Sound Echo/Distortion Poor Quality Problem Fix Solution


    This was very annoying but has a simple fix, I had an echo and the voice quality was absolutely horrible (it sounded like tin cans under water) if that helps describe it. It was extremely distorted. The simple Skype sound quality solution Go to "Options" -> "Sound Devices" Disable the "Allow Skype to automatically set my mixer levels" After doing this the sound qua........
  • 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........
  • mdadm/md-check how to check array integrity without rebuilding


    This doesn't seem to be widely known (maybe it's in some documentation that none of us read though)but there's an easy way to check the integrity of any mdadm array: sudo echo check > /sys/block/md0/md/sync_action -bash: /sys/block/md0/md/sync_action: Permission denied sudo will never work, this only works as root since echo is not actually a binary/command. It is built-into bash. /sys/devices/virtu........
  • md: data-check of RAID array md3


    This really made me nervous but notice the mdstat says "check". This is because in Ubuntu there is a scheduled mdadm cronscript that runs everyday on Sunday at 00:57 that checks your entire array. This is a good way because it prevents gradual but unnoticed data corruption which Inever thought of. As long as the check completes properly you have peace of mind knowing that your data integretiy is assured and that your hard drives are functioning properly (I'........
  • mdadm: metadata format 00.90 unknown, ignored.


    mdadm: metadata format 00.90 unknown, ignored. This happens with various versions of older mdadm such as mdadm - v2.6.7.1 - 15th October 2008 It is all because an extra 0 in 00.90 in /etc/mdadm/mdadm.conf that it doesn't like (it doesn't seem to cause any problem except that message though): Solution - Edit your /etc/mdadm/mdadm.conf and change 00.90 to 0.90 in your arrays: ARRAY /dev/md3 level=raid1 num-devices=2 metadata=0.90 UUID=f41a4644:6b2a05f........
  • 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........
  • VirtualBox some USB passthrough devices greyed/grayed out unavailable solution


    The solution is simple but it's a wonder why VBOX doesn't address it directly? Perhaps newer versions will but you have to add your user to the "vboxusers" group and then login and logout and you'll see the devices you wanted but couldn't access are now available. The weird thing is that the grayed out issue doesn't happen with all devcies but one notable thing is the Apple iPhone especially in DFU or Recovery Mode which is an big issue for some people.........
  • 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........
  • How to Enable SMART on a device


    smartctl -a -d ata -T permissive --smart=on /dev/sda -d ata is usually required for most SATA drives or you get an error. -T permissive is required if it's the first time you are running SMART on this device (it's not enough just to enable SMART in the BIOS) --smart=on is also required for the first time........
  • mdadm when a RAID 1 member dies


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