Discuss December 2023

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6 participants
5 discussions

SSD for Centos SWAP /tmp & /var/ partition
by Keith Roberts 03 Sep '25

03 Sep '25

Has anyone actually used a SSD in a Centos setup? My little experiment with a s/h WD drive for /tmp and SWAP partitions kicked the bucket on Wednesday, when the poor WD drive caught the click-of-death. It was a s/h drive to start with and lasted about 4 months. But that was without the /var/log/ partition being written to it, as I mounted that back onto /var/log from the original drive. So I had to install another (WD) drive, and repartion it and rebuild my RPM package database, from the backed-up Packages file. That seems to be all OK now. I'm wondering if it would be a good idea to use a new SSD for moving all the disk i/o to, that Linux likes to do so often. Plus putting SWAP onto a decent SSD should speed things up somewhat. Here's a short video of a laptop fitted with a SSD drive booting macOS, compared to a similar laptop booting from the standard HDD. The laptop with the SSD boots and loads some apps in 28 seconds. The other one takes twice as long. http://eshop.macsales.com/shop/SSD/OWC/Mercury_Extreme_Pro_6G/?utm_source=t… Kind Regards, Keith Roberts ----------------------------------------------------------------- Websites: http://www.karsites.net http://www.php-debuggers.net http://www.raised-from-the-dead.org.uk All email addresses are challenge-response protected with TMDA [http://tmda.net] -----------------------------------------------------------------

33 96

Problems with CentOS 8 kickstart
by Hooton, Gerard 23 Jun '25

23 Jun '25

Hi All, I am having problems with a kickstart install of CentOS 8 When I try to do a completely automated install using PXE/UEFI it get to the point where it reads the kickstart config file. Then I see the following message "kickstart install Started cancel waiting for multipath siblings for nvme0n1" This is what I have in the kickstart file # Clear the Master Boot Record zerombr # Partition clearing information clearpart --all --initlabel autopart --nohome --type=lvm --fstype=xfs ================ When I install from a USB drive it works OK and I have the following in /dev/disk/by-id lrwxrwxrwx. 1 root root 13 Jul 5 10:28 nvme-SAMSUNG_MZVL2512HCJQ-00BL7_S64KNE0R161810 -> ../../nvme0n1 lrwxrwxrwx. 1 root root 13 Jul 5 10:28 nvme-eui.002538b11102f46d -> ../../nvme0n1 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 wwn-eui.002538b11102f46d-part3 -> ../../nvme0n1p3 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-SAMSUNG_MZVL2512HCJQ-00BL7_S64KNE0R161810-part3 -> ../../nvme0n1p3 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-eui.002538b11102f46d-part3 -> ../../nvme0n1p3 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 lvm-pv-uuid-5Dg4mg-saHa-hJJ6-n5a8-MxBS-gdFi-5jPoNn -> ../../nvme0n1p3 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 wwn-eui.002538b11102f46d-part2 UNG_MZVL2512HCJQ-0-> ../../nvme0n1p2 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-SAMSUNG_MZVL2512HCJQ-00BL7_S64KNE0R161810-part2 -> ../../nvme0n1p2 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-eui.002538b11102f46d-part2 -> ../../nvme0n1p2 drwxr-xr-x. 2 root root 400 Jul 5 10:28 . lrwxrwxrwx. 1 root root 15 Jul 5 10:28 wwn-eui.002538b11102f46d-part1 -> ../../nvme0n1p1 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-SAMSUNG_MZVL2512HCJQ-00BL7_S64KNE0R161810-part1 -> ../../nvme0n1p1 lrwxrwxrwx. 1 root root 15 Jul 5 10:28 nvme-eui.002538b11102f46d-part1 -> ../../nvme0n1p1 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-uuid-LVM-qQok4M7AOo1TxZZ42GwZcbuVNBs0hnkKtEdtLjwJQyIdxJcSvPv8TEAjwYGMv6yU -> ../../dm-0 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-uuid-LVM-qQok4M7AOo1TxZZ42GwZcbuVNBs0hnkKAooqrczySYJyiHvUAUji9oScPN2cVi7J -> ../../dm-1 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-name-cs_uews027-swap -> ../../dm-1 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-name-cs_uews027-root -> ../../dm-0 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-uuid-LVM-qQok4M7AOo1TxZZ42GwZcbuVNBs0hnkK5HZXbR2ow5xKGuD7jVe4UPzZm2qRLLXI -> ../../dm-2 lrwxrwxrwx. 1 root root 10 Jul 5 11:07 dm-name-cs_uews027-home -> ../../dm-2 It's looks like that I am not doing the disk drive stuff in the config file correctly. -- Gerard Hooton. Senior Technical Officer School of Engineering. University College Cork. College Road. Cork. Ireland. Loc8: WDR-04-60G Tel: +353 21 4902296 Mobile: +353 852813491

3 7

Issues booting centos7 [dracut is failing to enable centos/root, centos/swap LVs]
by Yannis Milios 01 Feb '25

01 Feb '25

Hello, I'm having a strange problem booting a new centos7 installation. Below some background on this. [I have attached the tech details at the bottom of this message] I started a new CentOS7 installation on a VM, so far all good, o/s boots fine. Then I decided to increase VM disk size (initially was 10G) to 13G. Powered off the VM, increased the vhd via the hypervisor, booted from CentOS livecd, selected "recover my centos installation". Then I used the following sequence of commands to make the new vhd size "visible" to the o/s ... - ran fdisk /dev/sda and deleted partition 2. (This is the LVM partition where the o/s is stored. The first partition is /boot [xfs] partition *non lvm*.) - created a new partition with same starting sector as before deleting it, but a different ending sector (to reflect to the increased space). - set partition type to 8e (lvm), saved settings and exit. - ran pvresize and lvresize to make new space visible to the o/s.All good, I can see the space increase on 'lvdisplay centos/root'. - ran 'mount /dev/mapper/centos-root /mnt/root' to temporarily mount the o/s partition. - ran 'xfs_growfs /mnt/root' to resize the o/s fs to the new size. It was successful and I could actually chroot to the o/s and verify new disk size. - rebooted and tried to boot from hdd this time. Grub menu shows up and loads default kernel (3.10.0-862.9.1.el7.x86_64). - after initial kernel boot up process, booting continues to initrd and then it's where the problem starts... - looks like dracut has issues locating/enabling /dev/mapper/centos-root (lv) and as a result it cannot boot to the 'real' root fs (/). - while in dracut shell, I execute the following command sequence: 1. lvm lvchange -ay /dev/centos/root 2. lvm lvchange -ay /dev/centos/swap 3. ln -s /dev/mapper/centos-root /dev/root 4. exit ...and the o/s boots fine...so looks like the pv,vg,lv is detected properly while in initrd, but somehow dracut has difficulties enabling the root,swap LVs ? - While in o/s, I rebuild initrd by using: 'dracut -f -v -a lvm' Note, I have to use '-a lvm' as for some reason, if don't, the lvm utils (lvm,lvm_scan) are not being included to the initrd, not sure why this happens. After rebooting, same thing happens, I have to manually boot the system via dracut shell. I'm a bit stuck at this point, any clues what I'm doing wrong in here ? As I previously said, this is a new installation, so I could simply reinstall the whole thing, but I would rather try to find out some answer to why is this happening ... :-) [curiosity] Some additional details: ================== I've attached /run/initramfs/rdsosreport.txt file [generated while in inird] here: https://privatebin.net/?fdc4052c0c402884#gdB/QYR3IeR55SxUbjfrkZPQfJ7jMxiUxq… o/s ver=CentOS Linux release 7.5.1804 (Core) [root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 13G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 12.5G 0 part ├─centos-root 253:0 0 11.5G 0 lvm / └─centos-swap 253:1 0 1G 0 lvm [SWAP] [root@localhost ~]# cat /etc/default/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rd.shell rhgb" GRUB_DISABLE_RECOVERY="true"

4 11

resetting a serial port
by Robert Moskowitz 14 Dec '23

14 Dec '23

I have Centos 7 arm32 running on a Cubieboard and I am logged in as root on its serial uart from another system. On that system I use screen /dev/ttyUSB0 115200 Well it was working well for a couple days, but now only garbage comes across. Something messed up the serial link. pulling the usb cable to the usb/serial adapter does not reset things. I can ssh into the server and see root logged into ttyS0 How do I reset that serial port so that I can work on the system? thanks

5 7

mdadm: --update=resync not understood for 1.x metadata
by Strahil Nikolov 03 Dec '23

03 Dec '23

Hi All, Recently I had to update a host that uses raid1 for /boot and /boot/efi and I noticed that my resync service is failing with "mdadm: --update=resync not understood for 1.x metadata”. Does anyone know why 'mdadm-4.2-rc2.el8.x86_64.rpm’ supports it but 'mdadm-4.2-13.el8.x86_64’ not ? Why the version is not properly bumped if such drastic change is intentional ? Best Regards, Strahil Nikolov

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