Hello, I very recently added a third ssd cache drive to the cache (3 x 120GB SSDs). The new drive was precleared successfully before assignment. However since its addition whenever I read (not write) from the cache the entire array crashes hard. Since the array is now preforming yet another parity check (all caused by same issue) I want to remove this new disk as soon as the parity check has completed (back to just two 120GB drives). My question is... Can I just stop the array and un assign that disk and restart the array? What would be the effect on the data that resides on the cache (I do have it backed up)?

 

Oh, also... I believe that the issue is actually the sata controller and not the disk. Is it OK to have cache ssd's spread out on different sata controllers? Or should they all be on the same controller?

 

Thanks so much for any advice.

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Edited July 7, 20178 yr by manorfan

31 minutes ago, manorfan said:

Can I just stop the array and un assign that disk and restart the array?

 

No, that will result in an unmountable cache.

 

See here, though it may crash the same as a normal access:

 

 

 

If the server crashes during the normal remove procedure you can try to shutdown the server, physically disconnect that device and then start the array.

1 hour ago, johnnie.black said:

If the server crashes during the normal remove procedure you can try to shutdown the server, physically disconnect that device and then start the array.

 

Thank you for the link. If what's quoted here should be the case, then I will need to reformat the remaining cache disks and copy over my latest backups ( docker.img, appdata folder and any VM,s), shutdown and restart again? Would that be the correct process for this senerio?  

No, the pool should balance to the remaining 2 devices.

Thank you. Do you know if unraid will allow me to spread multiple cache drives over two different sata controllers? Or does it require them to share the same controller?

Edited July 7, 20178 yr by manorfan

You can use as many different controllers as you want.

One last question (hopefully). If/when I install a new sata controller card, can I just move the cache disks to it (unraid will recognize them on a different controller)? or would then need to be wiped and re installed on a new sata card?

 

Thanks You!!!

No problem with any AHCI/HBA controller, possible problem with RAID controllers.

The cache drives are presently on "RAID+AHCI" in the bios (HP xw8600 server). The card I have coming is non-raid.