Hot Spare disks (Storage Manager)

[fredbert]

Being new to >2 bay NAS I hadn't seen the Hot Spare options before. Now I'm thinking about current usage but also migrating the RAID in the future.

A few questions occur to me:

1. The documentation lists the RAID types that are supported for Hot Spare. I use SHR-1 and this is omitted from the list ('i.e.' is used in the help, not 'e.g.') yet Storage Manager would seem to get me to a point that I could use Hot Spare if I had a disk to do it with. Does anyone know if Hot Spare support SHR-1/2?
2. If a Hot Spare disk is activated by a RAID array does it get permanently assigned? i.e.
   1. Do you just remove the failing/failed disk and that's it? or
   2. Do you replace the failed disk with a new one and then that releases the Hot Spare?
3. [Not applicable to me] If you allow crow-device Hot Spare and the disk is permanently assigned on activation, can the disk be moved into the same device as the rest of the RAID?

What I'm thinking is this:

SHR-1 of 4 disks in a 5-bay NAS plus one Hot Spare disk: While not SHR-2 this could be the quickest way to recover resilience and have a future downgrade to a 4-bay NAS, if cash is tight if a box failure happens at a bad time.

Or is it just best to keep a cold spare on the shelf, unused?

 

[Telos]

Never use a hot spare unless you lack access to the NAS.

 

[WST16]

Or is it just best to keep a cold spare on the shelf, unused?

I’d rather keep it with the manufacturer until I need it. Prices keep on falling and capacities increasing. Why buy one and keep it on the shelf. I’ll buy it when I need it. Another (different) point of view.

Congratulations on your new 1520. I hope you like it and enjoy using it

 

[fredbert]

Never use a hot spare unless you lack access to the NAS.

It's that, increasingly unlikely event, being away on holiday/business.

It was more the accademic question of SHR-2 vs SHR-1 + hot spare. Where you keep a smaller RAID but with access to add back resilience should you need it.

The Hot Spare help pages lack explanation of what happens when a disk gets used. It just raised my interest.

I’d rather keep it with the manufacturer until I need it. Prices keep on falling and capacities increasing. Why buy one and keep it on the shelf. I’ll buy it when I need it. Another (different) point of view.

Congratulations on your new 1520. I hope you like it and enjoy using it

I can understand that logic being of the "short arms, deep pockets" persuasion.

DS1520+: Yep. I'm setting up Active Backup for the offsprings' educationally enforced Windows laptops ... so far it looks rather good. Adding another 8TB to the SHR will give 16TB and will be enough for the near future (Plex, Drive/Moments, ABB) and that'll release a 12TB WD external drive to be HB destination for the non-backup data.

 

[Telos]

It's that, increasingly unlikely event, being away on holiday/business.

Then plug it in before your leave. One concern I have is that with a hot spare, you have no time to investigate or ensure your backups are current. So if the rebuild fails, it could prove unfortunate.