Do you know how to set a free disk (big enough to be a member of all RAID groups) to be a "Hot Spare" available to all RAID groups in a Clariion CX3-20 using Navisphere 6?

I have created a RAID group with number of drives "1" and type "Hot Spare", but get the feeling that there's something else I need to do, to allow it to be used automatically by all the RAID groups in my Clariion.

I have read that one must make sure SATA disks don't become Hot Spares for FC RAID groups, and vica versa, and although my Array is all FC, I get the feeling that to set that up, there must be some notion of telling the Clariion which RAID groups (of type Hot Spare) can be Hot Spares for with other RAID groups.

Many thanks for reading!



Navisphere has the intelligence to know that a FC hotspare cannot sub for a SATA hotspare (and vice-versa). Hotspares should be created from the LARGEST size disk of a given interface type (e.g. a system with 1 x 450Gb 15K drive and 30 x 300Gb 15K drives should use the 450GB drive as a hotspare). recommended ratio of hotspares to data drives is 1:30 (for FC) and 1:15 (SATA). These are gross recommendations only so, you can flex this how you want.


dave graham corp systems engineer - EMC Atmos

  • That's great, it's what I've done, using the largest disk size to create a RAID group of type "Hot Spare". Will that make it automatically available to the array now? – Kenny Mar 4 '10 at 16:38
  • I have now bound a new LUN to the RAID group, so now in the "Hot Spare" RAID group there's a "Private LUN" with the Plus sign icon I can see in the "Navisphere Manager 6 Admin Guide" called "Hot spare in RAID Group or storage system". Hopefully that's made it available to the whole storage system? – Kenny Mar 4 '10 at 16:48
  • that Hotspare is now available for the whole system. just a note: HotSpare RG needs to be created then a HS LUN needs to be created on that HS RG. ;) good job. cheers, Dave – Dave Graham Mar 4 '10 at 20:08
  • Thanks Dave, that process is just what I was looking for. – Kenny Mar 5 '10 at 10:04

My understanding, is that you need to create a RAID group (of type Hot Spare) for each disk you have that is reserverd as a hot spare.

You can have one hot spare availible for multiple RGs, but once it is engaged (due to a failed disk) the hot spare won't be availibe to any other RGs

  • Thanks for your comments. I have created the RAID group, but am unsure if it's automatically now a Hot Spare for all existing RAID groups, i.e. if it will ever get used? – Kenny Mar 4 '10 at 12:33

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