[Areca RAID] RAID configuration disappears

If you’ve had a previously configured Raid Set on an Areca RAID controller and it all of a sudden disappears it can sometimes be salvaged. In the RAID BIOS: Raid Set Function -> Rescue Raid You’re then prompted to “Enter the Operation Key.” This is ambiguous in the documentation and there’s also a mispelling for […]

[MySQL/MariaDB/CentOS 7] mysqldump: Couldn’t execute XXXXX (Errcode: 24 “Too many open files”) (23)

MySQL/MariaDB will sometimes hit its open file limit when doing large mysqldump operations. On a lot of distributions you can raise the limit by adding the following line to the /etc/my.cnf file and restarting the service: open_files_limit=XXXX This doesn’t work on systemd controlled database services so you need to add the following lines to /etc/systemd/system/mariadb.service.d/limits.conf […]

[Linux/quotacheck] quotacheck: Cannot stat directory //var/spool/exim_incoming/scan/1erAzg-0007eX-E1: No such file or directory

When running quotacheck on a filesystem that isn’t read only it will error out and not finish if it’s unable to stat a certain file or directory. It does this because it assumes that there’s a problem with the filesystem. If your mail software is actively processing mail when running quotacheck it will get an […]

[OpenVZ/KVM/CentOS 7] No login prompt on boot

When converting CentOS 7 OpenVZ systems to KVM sometimes there is no login prompt after loading services. The machine is otherwise operating correctly. Here’s the fix to get the login prompt back: mv /etc/systemd/system/getty.target.wants/getty\@tty2.service /etc/systemd/system/getty.target.wants/getty\@tty1.service Afterwards the keyboard input may not work. Rebuilding the initial ramdisk will fix that: dracut -f

[RHEL 7/CentOS 7] Hanging Boot After Conversion to RAID1 (degraded RAID)

Quick fix… Rebuild the ramdisk. If you are using a rescue disk and are compiling for a different kernel version replace $(uname -r) with your kernel version: dracut –mdadmconf –fstab –add=”mdraid” –filesystems “xfs ext4 ext3 tempts devotes syses proc” –add-drivers=”raid1″ –force /boot/initramfs-$(uname -r) $(uname -r) Add the following to /etc/default/grub inside the quotes for the […]

[CentOS/Linux] WARN : [ipv6_add_route] ‘No route to host’ adding route ‘::/0’ via gateway ‘XXXX:YYYY:ZZZZ::1’ through device ”

When trying to add an IPv6 address to a server via the ifcfg-eth0 file resulted in the following error (redacted) upon restarting networking: RTNETLINK answers: Permission denied WARN     : [ipv6_add_route] ‘No route to host’ adding route ‘::/0’ via gateway ‘XXXX:YYYY:ZZZZ::1’ through device ” This was further confirmed by trying to add the IP […]

[Linux/NVME] Find serial number of NVME drive

Traditional methods of finding the serial number on a live Linux system do not work for nvme drives.  You can download the name-cli package from: https://github.com/linux-nvme/nvme-cli Once installed you will then have the “nvme” command and can find the serial number with the following command: nvme id-ctrl /dev/nvme0n1