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MD3000i change Raid5 to Raid10 on the fly?
Toying with the idea of purchasing an MD1000 with fifteen 400gb SAS drives to change my current 14 disc raid5 400gb sas to RAID10.
Possible? Advised? Any tips? Cautions?
JOHNADCO
847 Posts
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June 11th, 2009 09:00
It did seem wishful thinking. :)
Not the worst thing, I mean I can make disk copies, change the raid in that group then disk copy them back. Not to bad I guess.
Dev Mgr
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June 11th, 2009 09:00
The MD3000/MD3000i (at least on 07.35.22.61) has an option for a raid level change, but I'm not sure what the requirements are and I'm pretty sure if cannot move the data to a different set of drives for this.
JOHNADCO
847 Posts
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June 11th, 2009 10:00
It does look like I could add all the new disks to the existing raid 5 group as free and then change it?
Anyway to get an official Dell position on this change? Seems like it shouldbe do-able.
mrokkam
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June 11th, 2009 10:00
Well, Adding disks to a RAID 5 is allowed... and so is RAID Level Migration. Both are supported through the GUI and can be done on the fly. You should be able to add the 14 disks to the RAID 5 (limit is 30 disks total, so you are barely under that). And then you can migrate the whole thing to a RAID 10. Just make sure that you don't expand the Virtual Disk till you are done with the RAID Level Migration :-D. You can only have disk operation going on at a time, so it would be a slow and time taking process.
The only thing I can think of is that you will see a performance impact while it is going through the RAID level migration and it might take some time depending on the size of your VDs (Adding the disks shouldn't take too long).
The information Update provides instructions and some requirements for RAID level Migration
http://support.dell.com/support/edocs/systems/md3000i/multlang/ts/FR483-info%20update/MD3000i_IU2g.pdf (PDF Alert)
Based on this, I think you should be able to accomplish what you want to do.
So, what is the main reason for you to want to change to a RAID 10? You would be adding 14 disks and gaining ~400 gigs of space ;)
-Mohan.
Dev Mgr
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June 11th, 2009 11:00
You mention disk copy. Do you have the disk copy option enabled on your MD3000i (licensed feature)? If so, you could make the raid 10, then shut down the server using the raid 5, and do a disk copy from the raid 5 disk to the raid 10 (group/disk?... not sure if you have to create just the disk group or also the destination virtual disk). After this copy is done, you remove the mapping of the old disk to the server and add a map of the new disk to the server. Then boot up the server again.
JOHNADCO
847 Posts
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June 11th, 2009 14:00
That would be cool. But the 14 SAS drives in the production raid 5 sdisk group would have to be used for the raid 10. :(
On the changing? Speed increase is cool, but I am getting increasingly worried about the change of two drive failures before the hotspare can get rebuilt in. the RAID 5 seems plenty quick enough. I tested RAID6 on a test bed setup and the writes stunk, as in borderline good enough stunk. :)
All this would depend on the right MD1000 comming up on the outlet store. I can't afford a new one. The MD3000i in question here was also a furb from the outlet. It's been a real champ for serveral months now.