topic Re: Spare disk options for RAID array?? in Disk Enclosures

Spare disk options for RAID array??

Tom Lyczko — Fri, 08 Aug 2014 12:47:34 GMT

I have a RAID 5 array in a Proliant Gen8 DL380.

I don't understand the difference between the two spare drive options -- one is called Auto-Replace I think, the other is called I think Dedicated (the default I think).

Which option is the one to use when a disk goes bad and one wants the spare disk to kick in automatically??

I did not really understand HP's descriptions...

Thank you, Tom

Re: Spare disk options for RAID array??

Torsten. — Fri, 08 Aug 2014 12:59:34 GMT

In general you can assign a spare drive to a dedicated array or use it as a global spare for all your defined arrays. In "auto-replace drives" mode once the spare kicks in it becomes part of the array, if you replace the bad drive now the new drives becomes a spare, so there is no additional rebuild to make the former spare a spare again.

Re: Spare disk options for RAID array??

Tom Lyczko — Fri, 08 Aug 2014 13:01:00 GMT

That's what I thought...I don't understand why AutoReplace is not the default. Thank you, Tom

Re: Spare disk options for RAID array??

Torsten. — Fri, 08 Aug 2014 13:07:19 GMT

Maybe some want to have the spare at a dedicated slot, and AFAIR this feature came later and was not available from the beginning.

Without this setting if a drive fails the spare kicks in, then you replace the drive and the array will rebuild again to this replaced drive. The former spare becomes a spare again.

Re: Spare disk options for RAID array??

Tom Lyczko — Fri, 08 Aug 2014 15:33:59 GMT

I like better the Auto-Replace behavior, it's what I'm used to from our HP MSA SAN.

Is there a way to have the server send an alert when/if a drive fails and the spare takes over??

Thank you, Tom