{"id":528,"date":"2025-10-31T14:01:10","date_gmt":"2025-10-31T11:01:10","guid":{"rendered":"https:\/\/admin.danychrys.ro:4433\/?p=528"},"modified":"2025-10-31T15:03:48","modified_gmt":"2025-10-31T12:03:48","slug":"528-2","status":"publish","type":"post","link":"https:\/\/danychrys.go.ro\/web\/528-2\/","title":{"rendered":"Replacing a Faulty Disk in a RAID 1 Array (mdadm on Ubuntu 24.04)"},"content":{"rendered":"

1. Check RAID Status<\/span><\/h2>\n

Use the following command to inspect the current state of the RAID:<\/span><\/p>\n

sudo mdadm --detail \/dev\/md0<\/pre>\n
State : clean, degraded
\nActive Devices : 1
\nFailed Devices : 1<\/span><\/p>\n
\"\"<\/span><\/pre>\n
2. Mark and Remove the Faulty Disk<\/span><\/h2>\n
If the faulty disk is still present but failing, run:<\/span><\/p>\n
sudo mdadm --fail \/dev\/md0 \/dev\/nvme1n1p1<\/pre>\n
sudo mdadm --remove \/dev\/md0 \/dev\/nvme1n1p1<\/pre>\n
If the disk has already been physically removed, you can skip this step.<\/span><\/p>\n
3. Replace the Faulty Disk<\/span><\/h2>\n
Power down the server (if required), physically remove the faulty disk, and install a new one. Boot back into the system.<\/span><\/p>\n
4. Partition the New Disk<\/span><\/h2>\n
RAID 1 mirrors data inside partitions, not the partition layout itself. The new disk must match the layout of the healthy one.
\nClone the partition table from the working disk:<\/span><\/p>\n
sudo sgdisk -R=\/dev\/nvme1n1 \/dev\/nvme0n1<\/pre>\n
sudo sgdisk -G \/dev\/nvme1n1<\/pre>\n
-R=\/dev\/nvme1n1 \/dev\/nvme0n1: Copies the partition table.
\n-G: Regenerates the disk GUID to avoid conflicts.
\nCheck the layout:<\/span><\/p>\n
lsblk<\/pre>\n
Make sure \/dev\/nvme1n1p1 exists and matches the partition size of \/dev\/nvme0n1p2.<\/span><\/p>\n
\n
\n
5. Add the New Disk to the RAID Array<\/span><\/h2>\n
Once partitioned, re-add the new disk:<\/span><\/p>\n
sudo mdadm --add \/dev\/md0 \/dev\/nvme1n1p1<\/pre>\n
6. Monitor the Rebuild Process<\/span><\/h2>\n
Use this command to check the rebuild progress:<\/span><\/p>\n
cat \/proc\/mdstat<\/pre>\n
\"\"<\/span><\/p>\n
7. Confirm Rebuild Completion<\/span><\/h2>\n
When the rebuild is done, confirm the RAID status:<\/span><\/p>\n
sudo mdadm --detail \/dev\/md0<\/pre>\n
Expected output:
\nState : clean
\nActive Devices : 2
\nFailed Devices : 0<\/span><\/p>\n
\"\"<\/span><\/pre>\n
Optional: Update mdadm Config for Boot Persistence<\/span><\/h2>\n
Run the following to ensure mdadm config is saved for future boots:<\/span><\/p>\n
sudo mdadm --detail --scan | sudo tee \/etc\/mdadm\/mdadm.conf<\/pre>\n
sudo update-initramfs -u<\/pre>\n
With these steps, you’ve successfully replaced a failed RAID 1 disk and restored redundancy.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"
1. Check RAID Status Use the following command to inspect the current state of the RAID: sudo mdadm –detail \/dev\/md0 State : clean, degraded Active Devices : 1 Failed Devices : 1 2. Mark and Remove the Faulty Disk If the faulty disk is still present but failing, run: sudo mdadm –fail \/dev\/md0 \/dev\/nvme1n1p1 sudo…<\/p>\n","protected":false},"author":1,"featured_media":530,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-528","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tutorials","category-5","description-off"],"_links":{"self":[{"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/posts\/528","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/comments?post=528"}],"version-history":[{"count":20,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/posts\/528\/revisions"}],"predecessor-version":[{"id":553,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/posts\/528\/revisions\/553"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/media\/530"}],"wp:attachment":[{"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/media?parent=528"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/categories?post=528"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/danychrys.go.ro\/web\/wp-json\/wp\/v2\/tags?post=528"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}