• Centos 7 Reallocate logical volume space to another


    Do you hate how Centos 7 defaults to allocating most of your valuable space to /home even though it is a production server? Here is a quick guide on how to take back that space live, while online (of course make sure you have backups just in case something goes wrong!): First we will reduce our home dir by 100G: lvreduce -L -100G /dev/mapper/centos-home WARNING: Reducing active and open logical volume to ........
  • syntax error, unexpected T_SL in PHP Solution


    This happened in a PHPscript with heredoc but it could really happen anywhere. The issue was whitespace in code like this: $variable = ........
  • qemu-img resize howto


    The Correct Way To Resize In Place qemu-img resize kvmuserwindows2008dcetest.img +1G Image resized. Below is a common mistake that some users make they are trying to specify a new image name but it can be resized in place (just make sure the VMis NOT running and you've backed up the data in case something goes wrong). qemu-img resize kvmuser453111.img kvmuser453111-larger.img +5G New i........
  • not allowed to execute '/usr/bin/apt-get install eclipse' as root linux sudo user permisson issue and solution


    This is most likely to happen on a normal GUI system like Ubuntu or Linux Mint. If you or the user is meant to have sudo / root privileges it is as simple as editing the following files: Now assume your username is "iamtheuser" vi /etc/group adm:x:4:syslog,iamtheuser sudo:x:27:anotheruser,iamtheuser Find the above lines and add a comma and "ia........
  • linux how to answer yes to copy


    Have you have a command ask a question such as cp or move? You can do this: echo y|cp * /tmp/othercopy However it may still fail if your bashrc aliases have the "-i" flag see this post here.........
  • How to backup entire computer Linux Mint Ubuntu with tar


    sudo tar --ignore-failed-read -czvf mycomputer-backup.tar.gz --exclude=/home/otheruser/* --exclude=/proc/* --exclude=/sys/* / Note the --exclude clauses and modify/add according to your needs........
  • tar how to ignore failed reads and not exit


    This is an important feature a failed read can genuinely occur if a temporary file has been removed or if you try backing up a sysetm file in /proc /sys (which you shouldn't really anyway). The way to fix this is the following switch: --ignore-failed-read Example: sudo tar --ignore-failed-read -czvf mycomputer-backup.tar.gz --exclude=/home/otheruser/* --exclude=/proc/* --e........
  • How to extract view contents of initramfs image gzip'd


    Very simple browse to your /boot directory It does make more sense to extract the image in its own directory eg "initramfs-blabla-dir" as it will literally extract directly to the pwd. cp initramfs.img someotherdir cd someotherdir zcat initramfs-3.10.0-514.el7.x86_64.img | cpio -idmv........
  • 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........
  • Linux shows my drive as being dead is it really? Buffer I/O error on device sdb, logical block 0 sd 3:0:0:0: [sdb] CDB: Read(10): 28 00 00 00 00 00 00 00 08 00


    Normally the below would indicate a failing or failed drive. In this case the SATA port was unplugged and sometimes the Linux kernel/motherboard even with AHCIjust don't play nice and can't handle it. What happened is Iplugged in a new drive after removing another one. However the log shows that after the old drive was plugged in the Linux kernel kept complaining thinking the drive was there but not responding properly. This continued even with reseating........
  • yum Packages skipped because of dependency problems:


    Solution: yum -y install --skip-broken package-you-want-to-install Packages skipped because of dependency problems: php56w-mysql-5.6.30-1.w6.x86_64 from webtatic Error: Multilib version problems found. This often means that the root cause is something else and multilib version checking is just pointing out that there is........
  • heartbeat cross talk


    I do not understand why heartbeat would try to communicate with another system not considered part of the node: heartbeat: [8280]: WARN: string2msg_ll: node [otherbox.com] failed authentication ........
  • sed how to avoid escaping


    sed gets to be a pain and a real mess and is hard to read and understand when you have to escape things like / etc. Idid not realize until recently that you don't need to use / as a separator, you can use virtually any non letter or number character. Eg we have used # as the separator to avoid having to escape the forward slashes and in this way the command is plain, easy to understand, edit and saves time/hassle without the need for escaping. sed -i s#http........
  • How to manually save bash history


    This is useful in the case you are not properly logged in via an OpenVZ session or even a normal SSH session that you fear may go down(if the connection is broken the history is not saved). Save your bash_history like this: history -w ~/.bash_history You can always change the above to another file eg /tm........
  • Mysql how to backup/copy row from one table to another


    INSERT INTO articles_backup SELECT * FROM articles WHERE articleID="118" It is so simple we always recommend people do this when updating their database so you always have a backup. The above inserts the copy into the table "articles_backup" which has an identical structure. It selects the entry from "articles" where the articleID is "118" but of course you can adapter yours to whatever the situation is.........
  • mount -o bind permanent in /etc/fstab howto


    mount -o bind /somedir /anotherdir In /etc/fstab /somedir /anotherdir none bind 0 0........
  • status: { DRDY ERR } error: { ICRC ABRT } failed command: WRITE FPDMA QUEUED MCP55 Linux Errors


    [ 2868.041375] ata1: EH in SWNCQ mode,QC:qc_active 0x40 sactive 0x40 [ 2868.041554] ata1: SWNCQ:qc_active 0x40 defer_bits 0x0 last_issue_tag 0x6 [ 2868.041556] dhfis 0x40 dmafis 0x40 sdbfis 0x20 [ 2868.041874] ata1: ATA_REG 0x41 ERR_REG 0x84 [ 2868.042013] ata1: tag : dhfis dmafis sdbfis sactive [ 2868.042163] ata1: tag 0x6: 1 1 0 1 [ 2868.042301] ata1.00: exception Emask 0x1 SAct 0x40 SErr 0x400000 action 0x6 frozen [........
  • Dell CS24 NV5/NV7 Gigabyte GA-3CESL-RH Motherboard ROM Chip info


    If you remove the white label on the chip (near the CMOS battery) you will find the following details about it: SST 49LF080A 33-4C-NHE It is the PLCC32 type and can be pried and removed safely (but be very careful) with an eye glass flat head screw driver. If you just have a bad flash you may be able to reprogram your original or just buy another one with the part# above and reprogram it. This is great news for people who have bricked th........
  • HP XW9400 Motherboard In Desktop Issues


    Fortunately the format is EATX so an EATX case will work and the screw layout is standard. You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case). XW9400 Motherboard Issues Size: 12" x 13" Proprietary Power Connector Proprietary CPU Power Connector Proprietary Memory Power Connector Fan connectors are 4 pin so you will need some kind of adapter.........
  • Dell CS24,FS12 NV5 and NV7 1U Server Information & Parts


    Motherboard: Gigabyte GA-3CESL: http://b2b.gigabyte.com/products/product-page.aspx?pid=2658#dl Dell Part Numbers for the motherboard: R1232 R1232L R2232S SERVER MOTHERBOARD GENUINE 408P9 CN-0408P9 GA-3CESL Manual Download here RAMSlots: 16 (8 controlled by each CPU) RAMType: DDR2 ECC 5300P........
  • Linux Kernel EDAC errors EDAC MC0: UE row 0, channel-a= 0 channel-b= 1 labels "-": NON-FATAL recoverable (Branch=0 DRAM-Bank=0 Buffer ID = 0 RDWR=Read RAS=0 CAS=0 NON-FATAL recoverable Err=0x800 (Non-Aliased Uncorrectable Patrol Data ECC))


    I'm not sure why I'm getting these but all memory modules are the exact same and all passed memtest successfully although they are ECC. I've heard that ECC RAM can't be tested as well and the kernel seems to indicate they are non-fatl recoverable errors. I wonder if the BIOS has aggressive RAM timing or maybe the controller or motherboard is bad. [ 12.716515] EDAC MC: Ver: 2.1.0 [ 12.717771] EDAC MC0: Giving out device to........
  • Migrate Linux Mint OS from one drive to another


    mount -o bind /proc /sda2/proc mount -o bind /dev/ /sda2/dev mount -o bind /sys /sda2/sys chroot /sda2 mint / # mount -o bind /proc /sda2/proc mint / # mount -o bind /dev/ /sda2/dev mint / # mount -o bind /sys /sda2/sys mint / # chroot /sda2 mint / # cd ~ mint ~ # ls Desktop mint ~ # cd / mint / # ls bin Desktop dev-temp home&nb........
  • 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........
  • Dell Perc 6/i SATA benchmarks without battery


    The results are not bad, the Hitachi performs the same as it does in a SATA2 motherboard. However, the 2TB is much different, on a similar 2TB Toshiba I get about 198MB/s on a different motherboard vs the 2TB Hitachi which should produce similar results. This Dell Perc 6/i is on a PCI x8 riser card and is connected to a 12-port backplane. Adapter #0 Enclosure Device ID: 32 Slot Number: 0 Enclosure position: N/A De........
  • Dell Perci 6/i Firmware Upgrade Guide Tutorial


    One thing to remember is that you need MegaCli to do the flashing. You also need the correct file,I tried at least 2 different Perc 6 firmwares from Dell that kept getting rejected as corrupt by MegaCli(they were really the wrong version). I have an external PCI-E Dell 6 Perc/I butI chose images from the 'Integrated" on motherboard version as it was allI could find. They are different, and below is my first time finding success.........
  • 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........
  • kernel: EDAC MC0: CE page 0x0, offset 0x0, grain 1073741824, syndrome 0x1a, row 2, channel 0, label "": i3200 CE


    kernel: EDAC MC0: CE page 0x0, offset 0x0, grain 1073741824, syndrome 0x1a, row 2, channel 0, label "": i3200 CE I believe this is a hardware issue, it's usually bad RAM, incompatible RAM or bad timing or even a motherboard/RAM controller.........
  • rdesktop/Terminal Server Client Send Ctrl+Alt+Delete Howto


    The program itself catches it, just make sure it's actually focused on rdesktop and it sends Ctrl+Alt+Delete to the remote machine and not the local.........
  • WD 20EARX Dead Again


    Another new drive bad from the start: Jun 2 15:14:18 one-desktop kernel: [15895.386779] ata2.00: exception Emask 0x50 SAct 0x1 SErr 0x280900 action 0x6 frozen Jun 2 15:14:18 one-desktop kernel: [15895.386782] ata2.00: irq_stat 0x08000000, interface fatal error Jun 2 15:14:18 one-desktop kernel: [15895.386784] ata2: SError: { UnrecovData HostInt 10B8B BadCRC } Jun 2 15:14:18 one-desktop kernel: [15895.386788] ata2.00: cmd 60/0........
  • Powersupply Issue, Motherboard AHCI issue?


    This is the most I can get when plugging in a hard drive hot and only on some power connectors. [71656.314271] ata5: exception Emask 0x50 SAct 0x0 SErr 0x90a02 action 0xe frozen [71656.314277] ata5: irq_stat 0x00400000, PHY RDY changed [71656.314285] ata5: SError: { RecovComm Persist HostInt PHYRdyChg 10B8B } [71656.314294] ata5: hard resetting link [71660.360686] ata5: softreset failed (device not ready) [71660.360694] ata5: applying........
  • bash add numbers


    num=$(($onenum + $anothernum)) It's a bit silly that bash can't add normally as you'd expect (eg. $num + $num).........
  • Login and download all files script


    This is very handy if you're too busy and don't have time to download whatever files you need. The -D specifies the domains allowed, this is because I specified -H which means foreign hosts are allowed, if you don't restrict them you'll end up going to the whole internet via ads and other links just like a search Engine would follow. -l 0 specifies to go deep, to as many levels as possible/as exist. -e robots=off is important because robots.txt often says you can't vie........
  • pcnet32: eth0: transmit timed out, status 97fb, resetting - NIC card problem solution


    I've encountered this problem before and I believe it may affect other drivers (I could test but I don't have time). This was happening on my custom Linux system with the pcnet32 driver. pcnet32: eth0: transmit timed out, status 97fb, resetting (and some other kernel module tracing in dmesg) Basically it means the card is connected (it shows connected in full duplex etc.. and recognized if the cable is disconnected too) but no packets can be sent or received........
  • The Importance of a High Quality Power Supply/Power Supplies To Prevent Overheating/System Crash/Hardware Damage


    For years I've always built cheap systems believing that there is little difference in more expensive components when it comes to reliability and quality, I generally believe this still except for Power Supplies. I've always bought cheap cases with nice sounding 350-550W stock/cheap/crap power supplies and haven't had any issues for the most part until recently. One such case is an NGEAR case with a 550W Optimax power supply, I always read that these supplies don't produce the........
  • Asus VE247H 23.7" Inch LCD/LED Backlit Monitor Dead/Stuck Pixel Policy Complaint


    I've thought for awhile that Asus has been banking on its years old reputation for quality amongst gamers and enthusiasts and I think I'm right. My Asus VE247H Monitor with a supposed 2MS refresh rate has 1 red/stuck/dead pixel but fortunately it can only be seen on a non-true black picture or against a blue screen. I have several Asus products and find they're all of fairly poor quality. First of all their motherboards have given me the most issues of any brand, they te........
  • mdadm/Debian problem


    This is one in a series of weird things whichIthought was motherboard related (I RMA'd the motherboard), the RAM tests fine with memtest86 and I used badblocks on both RAID 1 members with no errors and smartctl is happy with them. Basically the array crashes the kernel a lot and has issues when writing. [112322.723465] md0: rw=0, want=14958668696, limit=1887460480 [112322.731077] attempt to access beyond end of device [112322.731087] md........
  • ifup eth0 SIOCSIFFLAGS: Cannot allocate memory Failed to bring up eth0 Centos Network won't work after kernel update and reboot


    ifup eth0 SIOCSIFFLAGS: Cannot allocate memory Failed to bring up eth0 This is on a Centos 5.5 machine with OpenVZ kernel 2.6.18-238.12.1.el5.028stab091.1PAE, I updated 3 systems with the same hardware to the same kernel and for some reason the network didn't come back. This only happened once the first time I booted into the new kernel and hasn't happened again but this is a serious issue for those running systems from remote locations such as a datacente........
  • Openvz Container IP not working suddenly Solution


    This may not apply to everyone but here is what happened to me. One day my IP connectivity for one container went dead, I could ping the hostnode from it and the hostnode could ping it but there was no external routing. I restarted the network service but it didn't help. I checked the routing table inside the VPS and the host and everything looked normal. Iadded another different IPon the same subnet to the container and it worked. Right away I st........
  • 2011 Best Laptop - HP 15.6" Laptop featuring AMD Athlon II P340 Processor (G62-420CA)


    My mother needed a new laptop and I recommended her the same one I would have bought myself or my wife, that means the cheapest possible laptop with the most features for the money. This HP shines at this price point and one thing that made me stay away from buying more and recommending HP/Compaq was the poor battery life. Not anymore, this model has an industry leading up to 4 hours of battery life. Key Factors for Choosing It: HDMI Out........
  • Understanding /etc/aliases from sendmail when using with postfix or other MTA's


    understanding /etc/aliases *remember to apply changes you need to run "newaliases" after editing /etc/aliases one thing I don't get is that it doesn't allow you to specify the whole e-mail address on the left-hand side eg: yourfullemail@domain.com: someotheremail@domain.com postalias: warning: /etc/aliases, line 109: name must be local (if you try the above) It works more like this: your........
  • VMWare bridged adapter not working: The network bridge on device vmnet0 is not running. The virtual machine will not be able to communicate with the host or with other machines on your network. Failed to connect virtual device Ethernet1.


    VMWare bridged adapter not working: Message from system: The network bridge on device vmnet0 is not running. The virtual machine will not be able to communicate with the host or with other machines on your network. Failed to connect virtual device Ethernet1. I'm not sure how to fix this but one of the issues is that my eth0 became eth1 after moving my hard drives to a new motherboard. I have run the vmware-config.pl but this did not resolve the issue.........
  • FUSE/Curlftpfs mount ftp account as drive partition in Linux


    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........
  • Intel Corei5 750 Complaint/Onboard Video Issue on Intel H57 chipset not working


    Do you have an LGA1156 board and wonder why your onboard video isn't working? It's probably because there is no GPU integrated on the board itself, it is supposed to be on the CPU and new CPU's from Intel don't come with it! I was shocked to learn that you can buy a motherboard with onboard video which doesn't work. Inever knew it was being done or possible, but to make it worse the latest Core i5's don't have video on the die of the CPU. This means having on........
  • Gigabyte GA-H57M-USB3 Complaint Review/Comments


    I'm not impressed with this motherboard, I was impressed with my Gigabyte AM3 board which seems to work flawlessly. Everyone knows that the firmware is flawed, even though I have the F6, it still seems that the system doesn't reset properly or quickly enough. Another HUGE problem is that in most Linux kernels the NIC won't work (if you try 10 times by rebooting it might). I also notice that you need to power down for it to work. This board does not seem very com........
  • Unixbench Score on Core i5 750 with OpenVZ Kernel vs Xen/Openvz


    This was unbelievable how much the Xen kernel slows things down, keep in mind both tests were done on the hostnode, one was with the Openvz-Xen hybrid kernel and the other was just OpenVZ. You can see the performance difference is nearly 300% better when not using the Xen kernel. OpenVZ-Xen Kernel Test Results (I was wondering what was wrong/so slow with my Core i5!) # # # # # #&n........
  • Windows install blue screen of death caused by faulty optical/DVD-RW drive.


    I took an educated guess because it kept happening at the same spot when loading the XP install. I thought it was the hard drive or motherboard. But it turns out my heavily used but loved NEC 3500 DVD-RW drive was the culprit. After disconnecting it and swapping it for another much beloved Pioneer DVD-RW, everything has gone smoothly. I never ran into this or many issues because I've hardly used this drive since moving it to another Desktop years ago. I actua........
  • 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........
  • The New Chips on the Block


    The New Chips on the BlockThe New Chips on the Block By Bruce Gain Story location: http://www.wired.com/news/infostructure/0,1377,67795,00.html 02:00 AM Jun. 13, 2005 PT We have embarked upon a new era in x86 PC computing -- so say chip giants AMD and Intel following their launches of dual-core PC processors. So how will dual-core processing change your PC computing experience? Our FAQ should help you decide whether or when you sho........
  • ECS K7S5A Motherboard System Take Up To 2 Minutes To Boot


    ECS K7S5A Motherboard System Take Up To 2 Minutes To BootHi guys, My motherboard is very strange. Sometimes it will take up to a few minutes to post. I have no idea it suddenly started doing this. I have tried everything and all I can figure is that it is somehow related to the USB ports possibly. Why do I say this? Because if I disconnect my scanner the problem occurs less frequently. I only have a printer hooked up to USB now and by........
  • Other Security Web Sites


    Other Security Web SitesSeveral websites actively track security issues. This list provides you with the major providers of security information on the Web. Many of these organizations also provide newsletters and mailings to announce changes or security threats: Center for Education and Research in Information Assurance and Security (CERIAS) CERIAS is an industry-sponsored center at Purdue University that is focused on technology and relate........
  • Tyan S2735-8M motherboard/Rackable Systems 1u Server 100mbit NIC not working even when enabled in the BIOS


    Itried everything Icould think of, and of course even with the NIC enabled in the BIOS nothing was working. The light would flash when you plugin the cable for a second, but that's all. Due to another issue I'm about to post about (server is not compatible with 1TB/1000Gig Hard Drives), I updated the BIOS. I didn't even know the 100mbit NICs were not working untilI decided I should test each NIC one by one. Inoticed that only 1 server out of........
  • Have an OpenVZ VPS/Linux Virtual Private Server and nothing works right?


    A VPS Server I had just wasn't working right, code that I migrated there just wasn't working. For example, it kept telling me the connection to the database was unsuccessful, halfway through iterating through results it already had. Then I realized it wasn't my code. Ichecked my /proc/user_beancounters and found this: cat /proc/user_beancounters Version: 2.5 uid resource held maxheld barrier limit failcnt........
  • MySQL Restoring And Dumping/Backing UP MySQL Data/Tables/Databases


    Backing MySQL Databases Backing Up/Dumping All Mysql Databases To A Single File mysqldump --all-databases -u admin -p > allmysqldatabases.sql The "-all-databases" clause is pretty obvious isn't it? It means that it will backup all databases. The "-u admin" means login using the user "admin", if you h........
  • 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........
  • RTL8111/8168B R8169 Gigabit Link slow speeds


    This is the Intel Atom 330 motherboard with integrated Realtek Gigabit NIC (Intel Desktop Board D945GCLF2 Motherboard W/ Atom 330 1.6 GHz Dual Core Processor - Mini-ITX) I cannot achieve more than 15 MB/s, even doing a local transfer through eth0 to it's own IP. 100% 95MB 15.9MB/s 00:06 So this is not a cabling, switch or hardware issue, it seems like a driver or chipset limitation problem. Here is my........
  • Rackable Systems and their Microslice Clustered 1U Servers


    Ithink there has been a lot of negative press towards Rackable Systems. We will give their new solution credit that it is marketed very well, and comes prepackaged and ready to go. But let's cut through the hype of both sides, the people who love this concept and the people who hate it. What Rackable Systems have done is a first, to minimize space, power and costs into small servers. This is great, and many companies have already built their own servers based........
  • Latest Articles

  • Linux Ubuntu Cannot Print Large Images
  • Cannot Print PDF Solution and Howto Resize
  • Linux Console Login Screen TTY Change Message
  • Apache Cannot Start Listening Already on 0.0.0.0
  • MySQL Bash Query to pipe input directly without using heredoc trick
  • CentOS 6 and 7 / RHEL Persistent DHCP Solution
  • Debian Ubuntu Mint rc-local service startup error solution rc-local.service: Failed at step EXEC spawning /etc/rc.local: Exec format error
  • MySQL Cheatsheet Guide and Tutorial
  • bash script kill whois or other command that is running for too long
  • Linux tftp listens on all interfaces and IPs by DEFAULT Security Risk Hole Solution
  • python import docx error
  • Cisco Unified Communications Manager Express Cheatsheet CUCME CME
  • Linux Ubuntu Debian Missing privilege separation directory: /var/run/sshd
  • bash how to count the number of columns or words in a line
  • bash if statement how to test program output without assigning to variable
  • RTNETLINK answers: Network is unreachable
  • Centos 7 how to save iptables rules like Centos 6
  • nfs tuning maximum amount of connections
  • qemu-kvm error "Could not initialize SDL(No available video device) - exiting"
  • Centos 7 tftpd will not work with selinux enabled