# Best way to replace failed RAID disk **URL:** \ **Category:** Rocky Linux Help & Support\ **Tags:** rocky-linux-9\ **Created:** [February 21, 2024, 8:31pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961 "2024-02-21T20:31:58Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![johni](https://avatars.discourse-cdn.com/v4/letter/j/b38774/32.png) [@johni](https://forums.rockylinux.org/u/johni)\ **Post date:** [February 21, 2024, 8:31pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/1 "2024-02-21T20:31:58Z")
After power failure server rebooted with one software RAID (md122) in degraded status: > State : clean, degraded > Number Major Minor RaidDevice State > 0 8 1 0 active sync /dev/sda1 > - 0 0 1 removed Tried gdisk on the affected drive /dev/sdc and reports: > GPT fdisk (gdisk) version 1.0.7 > Problem opening /dev/sdc for reading! Error is 2. > The specified file does not exist! Obviously smartctl doesn’t respond so I can’t find the serial number of the defunct disk to identify it. In past I have lost all data on a RAID cluster when replacing the drive so I want to be very careful I give right instructions in proper order to mdadm this time! What is the proper procedure or where should I look to find it and how can I identify the proper drive to replace (all drives on this machine are WD Blue SSD’s). ---
**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\ **Post date:** [February 21, 2024, 8:57pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/2 "2024-02-21T20:57:23Z")
> [@johni](#): > > Obviously smartctl doesn’t respond so I can’t find the serial number of the defunct disk to identify it. But you can get the serial numbers of all the non-broken disks? That should leave one physical disk with “unseen” serial. ---
**Author:** ![johni](https://avatars.discourse-cdn.com/v4/letter/j/b38774/32.png) [@johni](https://forums.rockylinux.org/u/johni)\ **Post date:** [February 21, 2024, 10:44pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/3 "2024-02-21T22:44:27Z")
Thanks. Yes, I had thought of that but it means I have to pull all the other disks because the serial numbers are on the inside. I was hoping there might be an easier way! Given unfortunate prior experiences with RAID I am hoping that someone will let me know **exactly** how to replace this disk. In the past the failed disk didn’t go to status “removed” until I issued an mdadm --fail command and then a --remove. Has this been automated? ---
**Author:** ![ganphx](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/ganphx/32/2381_2.png) [@ganphx](https://forums.rockylinux.org/u/ganphx)\ **Post date:** [February 21, 2024, 10:58pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/4 "2024-02-21T22:58:36Z")
> **[Chapter 19. Managing RAID Red Hat Enterprise Linux 9 | Red Hat...](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_storage_devices/managing-raid_managing-storage-devices#replacing-a-failed-disk-in-raid_managing-raid)** > > Access Red Hat’s knowledge, guidance, and support through your subscription. ---
**Author:** ![johni](https://avatars.discourse-cdn.com/v4/letter/j/b38774/32.png) [@johni](https://forums.rockylinux.org/u/johni)\ **Post date:** [February 22, 2024, 7:07pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/5 "2024-02-22T19:07:11Z")
Followed those instructions and RAID cluster is now active again and resync. A number of questions arise from this exercise but I’ll do a different post on them as I think many people will encounter the same questions. Thanks to both of you; without that pointer I might have made a pig’s ear out of the whole recovery. ---
**Author:** ![system](https://us1.discourse-cdn.com/flex020/uploads/rockylinux/original/1X/91b7219eec10e30013422e4df76c1d898711a5d5.svg) [@system](https://forums.rockylinux.org/u/system)\ **Post date:** [April 22, 2024, 7:07pm UTC](https://forums.rockylinux.org/t/best-way-to-replace-failed-raid-disk/12961/6 "2024-04-22T19:07:55Z")
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