I had a 5 drive Raid5 array and I've had two drives fail. I have fresh drives to swap out, but when I'm trying to start it it complains '/dev/md/0 assembled from 3 drives - not enough to start the array'
the superblock data from one of the original drives:
mdadm -E /dev/sdb /dev/sdb: Magic : a92b4efc Version : 1.2 Feature Map : 0x1 Array UUID : eece6340:50c5f548:fec6e083:8e175d25 Name : nas2:0 (local to host nas2) Creation Time : Sat Jun 11 15:08:47 2016 Raid Level : raid5 Raid Devices : 5 Avail Dev Size : 3906767024 (1862.89 GiB 2000.26 GB) Array Size : 7813533696 (7451.57 GiB 8001.06 GB) Used Dev Size : 3906766848 (1862.89 GiB 2000.26 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Unused Space : before=262056 sectors, after=176 sectors State : clean Device UUID : f99f8f44:bbf30563:35183897:5563d56a Internal Bitmap : 8 sectors from superblock Update Time : Sun Aug 12 15:01:12 2018 Bad Block Log : 512 entries available at offset 72 sectors Checksum : 3c38edaa - correct Events : 364523 Device Role : Active device 0 Array State : AA..A ('A' == active, '.' == missing, 'R' == replacing)
and here is the output from attempting to assemble :
mdadm: /dev/sdb is identified as a member of /dev/md/0, slot 0. mdadm: /dev/sdf is identified as a member of /dev/md/0, slot 4. mdadm: /dev/sdc is identified as a member of /dev/md/0, slot 1. mdadm: added /dev/sdc to /dev/md/0 as 1 mdadm: no uptodate device for slot 2 of /dev/md/0 mdadm: no uptodate device for slot 3 of /dev/md/0 mdadm: added /dev/sdf to /dev/md/0 as 4 mdadm: added /dev/sdb to /dev/md/0 as 0 mdadm: /dev/md/0 assembled from 3 drives - not enough to start the array. mdadm: looking for devices for further assembly mdadm: No arrays found in config file or automatically
Is there anyway to clone superblock data (like dd) to a new drive to allow the array to be assembled?