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MD3200 - 8 disk RAID5 to ? disk RAID 10 possible?
I currently have an MD3200 with 8 of 12 slots populated (always fill all slots when you buy, people!)
The size and quantity of drives was chosen early on in my project when I had intended to use RAID5. I'm realizing now that I would be better off with RAID10. 7 of the 8 disks are in a RAID5 Disk Group (the 8th is a global hot spare). Two questions:
-Is it even possible for the MD3200 to migrate from RAID 5 to RAID 10? When I right click the disk group in MDSM and select Change->RAID Level->RAID 1 or 10... is not grayed out, but I have data on the array now and I can't test it.
-Assuming it is possible, obviously going from RAID 5 to RAID 10 with the same number of disks would not be possible, since RAID 10 would have a lower capacity (unless it's capable of doing this as long as less than the capacity of the RAID10 is unallocated.. not sure). I know since I am using 7 disks and have 1 hot spare, I would need to add at least one more to continue having a hot spare (how necessary is this with RAID 10, anyway?). Is there any other requirement I should know about?
Last time I checked with my rep there were no additional SAS drives available for sale, so this is all assuming I'll be able to buy more some day (joke).
DELL-Kenny K
685 Posts
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March 16th, 2012 08:00
After looking into this, you will lose a little space but when you add that 8th drive into the array you will be able to convert it to a RAID 10 with no issues.
DELL-Kenny K
685 Posts
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March 15th, 2012 11:00
Going from a RAID 5 to a RAID 10 you are correct you would need to add an 8th drive so there would be an even number. If you are still able to keep a hot spare drive in the system it would be good just for safety precautions. It isn't quite as necessary as with a raid 10 you can lose a drive from each mirror with out losing data, just as long as you don’t lose both drives of that mirror you will be okay. Make sure you are aware that you will lose some of the total capacity when going to the RAID 10. Below is a link for the owners manual that explains the raid level migrations.
support.dell.com/.../MD3200.pdf
It all starts on pg. 45. Let me know if you need anything else.
avtiuk
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March 16th, 2012 05:00
Would you happen to know if the capacity of the new RAID10 has to be greater than that of the RAID5, or can it be less as long as it has enough to cover however much of the RAID5 has been allocated?
avtiuk
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March 19th, 2012 05:00
Thanks Kenny, glad to know I haven't locked myself in to RAID5