Adding disks to a raid60 array, need resize help.

JeSuisNerd · 2017-07-04 23:30:51

This seems the best board to post on as System Administration has closed. Mods please move if inappropriate here.

I recently built a NAS server running Arch, with 16 drive trays and only 8 originally populated. After a lot of research, raid60 seemed to give the balance I needed between protection, performance, and capacity, so I split the drives into two raid6 arrays (md60, md61) of four drives each, and striped them together in a raid0 array (md0).

Today, I added four drives to the enclosures - two into each raid6 array, which have successfully grown to the new size. However, I can't get the raid0 array to expand to fill out this space, which I had previously thought was possible - but now I'm not so sure. My problem is analagous to in-place swapping a raid0 member for a larger drive, and I haven't found a solution for that either.

mdstat of relevant arrays:

md0 : active raid0 md61[1] md60[0]
      15627286528 blocks super 1.2 512k chunks

md60 : active raid6 sde[1] sdf[3] sda[0] sdb[2] sdd[4] sdg[5]
      15627548672 blocks super 1.2 level 6, 512k chunk, algorithm 2 [6/6] [UUUUUU]
      bitmap: 2/30 pages [8KB], 65536KB chunk

md61 : active raid6 sdi[2] sdh[0] sdj[4] sdk[1] sdl[3] sdn[5]
      15627548672 blocks super 1.2 level 6, 512k chunk, algorithm 2 [6/6] [UUUUUU]
      bitmap: 1/30 pages [4KB], 65536KB chunk

As you can see, each raid6 array is grown to 15TB, and the raid0 is still taking up half the combined space (15TB).

Oh, and the regular "grow" command won't cooperate, making me dread that I'll have to start from scratch:

sudo mdadm --grow /dev/md0 --size=max
mdadm: Cannot set device size in this type of array.

Question / TL;DR: Is it possible to tell mdraid level 0 to expand to fill a capacity change of its member drives? It would be a massive pain to try backing up this data to re-make the raid0 fresh.

Thanks for reading

Last edited by JeSuisNerd (2017-07-05 00:42:39)

Arch Linux

#1 2017-07-04 23:30:51

Adding disks to a raid60 array, need resize help.

Board footer