• virt-resize: error: libguestfs error: could not create appliance through libvirt.


    This is caused because the user is running as qemu for virt-resize and if qemu does not have privileges to read from the source and write to the destination, it will fail with the below. So either change the uid of qemu or change the ownership of the source and target. Solution: export LIBGUESTFS_BACKEND=direct virt-resize --expand /dev/sda2 /root/kvmtemplates/windows2019-eval-template.img /root/kvmguests/kvmkvmuser4515........
  • dd how to backup and restore disk images including compression with gzip


    dd is a very handy tool and there are some more practical things we can do. For example if we want to dump a 3TB drive and want to preserve it and only 200GB are being used on the 3TB we can save a lot of space with gzip. Backing Stuff up with dd How to Use dd to backup a raw hard drive and tar gzip at once Change /dev/sda to the drive you want to backup Change /mnt/extras........
  • Ubuntu Debian Linux Mint r8169 r8168 Network Driver Problem and Solution


    This problem has been around forever, Linux seems to think it is fine to use the r8169 driver for an r8168 NIC but this often causes problems including the link not working at all. In my case ethttool shows the link up and detected but it simply does not work especially on a laptop that has been resumed from suspension. Sometimes it takes several minutes for it to work or to unplug and replug the ethernet. Here is the solution: Install th........
  • Proxmox Breaks Storage/LVM Backing If Killing QEMU-IMG


    I tried to stop a qemu-img copy or clone and it broke everything. It was fine to "stop" it from the GUI but a process still persisted so I killed the relevant qemu-img and the kernel went crazy. It also may not have helped that I tried to lvremove a different volume (an unused disk). But either way it breaks LVM (you cannot even run lvdisplay) so a reboot is necessary. Jan 17 06:45:21 testserver kernel: [ 5680.439337] systemd-udevd D 0&nbs........
  • 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........
  • 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........
  • EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670:


    Jun 12 10:30:53 kernel: [724514.291670] EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670: rec_len % 4 != 0 - offset=216, inode=2553603, rec_len=94, name_len=84 Jun 12 10:30:53 kernel: [724514.292400] EXT4-fs error (device md20): ext4_add_entry: bad entry in directory #2552670: rec_len % 4 != 0 - offset=216, inode=2553603, rec_len=94, name_len=84 This happened when an unprivileged user was backing up a Windows filesystem, once they ha........
  • KVM/QEMU Base/Template Images and the power they provide


    qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2 Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB -b the source/base image -f format is qcow2 and the location of the destination image What is so special about this? It's even quicker than creating a template with OpenVZ but this is an actual OS. It saves time a........
  • 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........
  • Writing/Burning a data CD-R/DVD-R or DVD+RW in Unix/Linux


    There's a lot of outdated information and confusion for system administrator's out there. One annoying task for many an Administrator has been backing up data in Linux. You don't need any GUI tools such as K3B or GnomeBaker. Both are excellent tools but for veteran command line users working remotely, using the keyboard is a great and possibly automated way to save yourself pain and hassle. At a later date we'll cover how scripting can automatically backup certain........
  • Latest Articles

  • Huion and Wacom Tablets How To Install in Linux Mint / Ubuntu and make the stylus work properly
  • ffmpeg how to cut certain parts of video out
  • ffmpeg how to concat and join two video clips
  • mencoder instead of ffmpeg to join or concatenate video files with different audio streams
  • Linux How To Stop Missing Drive from Halting Boot Process in fstab
  • How To Replace Audio Track of Video using ffmpeg
  • qemu-img convert formats vdi vmdk raw qcow2
  • Linux and Windows Dual Boot Crazy Time Issues
  • dynagen / dynamips 100% high CPU usage solution - how to set the idlepc value
  • How To Setup a Cisco CME (Cisco Manager Express) Virtual Router under Linux using dynamips and dynagen
  • Linux Mint Ubuntu Debian CentOS Dual Boot Install Issues
  • Linux Mint Ubuntu Debian Centos RHEL no sound solution
  • Linux Mint/Debian/Ubuntu/Centos Installer black grub screen and blank screen after trying to boot installer or main OS
  • Linux Mint Dual Boot Install Avoid Wiping our your Main C: drive /dev/sda MBR and EFI
  • QEMU-KVM soundhw deprecated how to enable sound in QEMU 4.x series
  • Virtualbox Error Cannot register the hard disk because a hard disk with UUID already exists solution
  • kernel: [549267.368859] mate-terminal[7871]: segfault at 2000000101 ip 00007f5d0a9548f0 sp 00007fff7012c610 error 4 in libgobject-2.0.so.0.4800.2[7f5d0a920000+52000]
  • apcupsd how to setup and monitor APC UPS units
  • How To Password Reset, Recover, Bypass, Remove and Unlock on Windows 10,8,7,Vista,XP,NT,2000,2003,2008,2012,2016,2019 Administrative Login Programs
  • Nvidia Ubuntu Linux Screentearing Video with solution driver