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i would like to know, incase im having an MD1000, with 2 disks of 450GB, and 2 disks of 600GB,

is it possible to attach 600GB disk as a global hot spare, that will be used for both 450 and 600 if needed? or the MD1000 won't know what to do in this case

thanks for your time


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If I'm not mistaken the MD1000 will use a single hot spare for a failed disk in any disk group if it's configured as a global hot spare (automatic configuration). So yes, I believe this is a perfectly acceptable configuration.

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im not talking about assigning a hot spare while creating the virtual groups, im talking about assigning a 600GB disks as GLOBAL hot spare (it's under the physical disks menu in dell open manage) it assign disk to be hot spare for all the disks... so i wanna know if setting a 600GB disk to be a global hot spare will make it a replaceable for both 450GB and 600GB incase needed – OrenM Oct 7 '10 at 12:23
Agreed with Joe, I believe this works find so long as the disk is the same type (SAS) and equal to the largest disk in an array. – Chris S Oct 7 '10 at 12:46
@OrenM: Yes. That's correct. Configure it as a hot spare and you should be fine. @Chris S: That's my understanding as well. – joeqwerty Oct 7 '10 at 22:40
@OrenM: In addition, if you've got an MD1000 then it goes without saying that you're running the Modular Disk Storage Manager client on at least one machine, you can go into the help system and read all about hot spares and how to configure them, assign them, etc., etc. – joeqwerty Oct 7 '10 at 22:56

you generally can't link one disk to two RAID pools. each pool should have a hot-spare of the same size as the rest of the disks, else space is wasted. your 450GB pool should have a 450GB hot-spare and your 600GB pool should have a 600GB hot-spare.

ADD: on further thought some raid cards will allow setting of system-wide hot spares. depends on the card really. check the manual.

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i dont mind the space will be waisted, im more into know if it is possible to use 1 disk for both pools, as long as it can hold both 600 and 450 – OrenM Oct 7 '10 at 11:37
now that I come to think of it, depending on the BIOS on the raid card, you could set a system-wide hot spare disk which will replace a failed disk in either pool. check the firmware manual for your card to see if this is possible. normally you assign one or more hot spares per pool. – Khushil Oct 8 '10 at 17:16

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