ML350 SA641 Online Spare

[Duane Putnam]

I didn't realize a single online spare could be used to back up failed drives from two different arrays simultaneously. I didn't find this in the documentation, but I had an opportunity to witness it on an ML350 G4 w/ SA641. Very cool.

[Brian_Murdoch]

Hi Duane,

Yes that feature has been around since the earlier Smart Array controllers in the Compaq days. As long as the spare is the same capacity or greater than the drives in the raid sets it provides backup for then it will work. In other words a 146Gb drive can act as a spare for raid sets with 9Gb, 18Gb, 36Gb, 72Gb and 146Gb members. The drive adopts the geometry of the unit it is replacing. So the 146Gb drive can "act" like an 18Gb drive for example. When the original failing drive gets replaced the 146Gb drive goes back as a spare. Well that's the theory anyway.

Regards,

Brian

[Duane Putnam]

Thanks for the info Brian. The interesting part of this, for me anyway, is that a single online spare was working to back up two different drives that had failed in separate arrays *simultaneously*. I didn't realize a single online spare could do such a thing.

[mstoumba1]

Also since the drive is powered down it isn't getting any wear and tear until the system needs it.