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23763
March 31st, 2014 16:00
Swapping to larger drives, but going down two, possible to remove them from array and then expand?
I have a R710 with a PERC 6/i, running Win 2008 R2. I have a small drive for the OS, the the other 5 bays are full with 1 TB drives in a RAID-5 array.
I need to add more storage, so I want to buy three 3TB drives. I plan on removing one old drives and then putting in the new, larger one. I'm assuming it will take 1 of the 3 TB and repair. Leaving 2 TB free on the disk. I will repeat this step two more times, which will result in three 3TB drives with 6 TB of free space not used in the RAID.
Is it possible to have the controller expand storage in my existing RAID-5 array to the free space, and then remove the two remaining 1TB drives from the array?
Does that make sense? Is this even possible? Or am I going to have to backup the data onto another storage device and remove the array and just start a new one with the three 3TB drives and copy the data back?
theflash1932
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March 31st, 2014 20:00
This isn't going to work:
1) The PERC 6 will NOT take 3TB drives; the max size is 2TB.
2) You cannot remove disks from an array - your 5x1TB RAID 5 must always have 5 or more disks (you can add but not remove). Even using the same number of disks, is it not possible to make the array/VD smaller.
3) Even if you used 2TB disks, there is no way to make the RAID 5 bigger using the additional space on the disks - with 5 disks in RAID 5, it will remain the same size. The only thing you can do with the new space is create a second RAID array across the disks (called 'slicing'). This new VD will be handled by the OS as a separate 'disk'.
Keep in mind if backing up and restoring to a larger array, that if the VD ('disk') is larger than 2TB, the 'disk' MUST first be converted to GPT, and UEFI enabled as the boot mode (instead of BIOS). Be sure your backup software is capable of restoring a BIOS-based install to a UEFI system (and MBR 'disk' to GPT 'disk').
gregom
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April 1st, 2014 08:00
Thanks for the reply. I'm assuming there is no firmware upgrade that will change this? Who makes a RAID controller that doesn't support over 2TB? There are many controllers considerable older that do. I'll check for a new firmware but if that is indeed the case that is... well, lame.
Ok so I can't remove disks... so I guess i'll just copy my data to a temp drive and then delete the array and just start over with a new array with the new drives.
I did initially format as a GPT disk and converted it to dynamic. So I can expand the volume when I need. It has worked great but now all my drive bays are full.
theflash1932
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April 1st, 2014 09:00
No firmware update will "fix" it - it is a limitation of the hardware and a firmware update will not make it see +2TB drives. Dell's firmware will not, and LSI's firmware (if you force-flash the Dell controller with LSI firmware) will not. If you haven't been at this very long, keep in mind the PERC 6/i is 7 years old. LSI makes the Dell PERC controllers, and they make controllers for most of the major OEM's, but the limitation also exists on Adaptec and every other RAID controller manufacturer. Also realize that this is a RAID implementation limitation - controllers that support JBOD or pass-through can typically see/use +2TB disks in JBOD mode, even if fairly old (the low-end SAS 6/iR has a disk limit of 2TB when configuring RAID, but can use larger than 2TB if left unconfigured (non-RAID)). (I realize that nearly all current controllers do support +2TB in RAID - I'm talking about "last-generation" controllers.)
You could replace each of your 1TB drives with 2TB drives, in lieu of a backup/restore, but 2TB is as large as you can go on the PERC 6.
Another option would be to migrate your VD to an H700:
gregom
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April 1st, 2014 10:00
Bummer... is there a newer PERC controller I can buy and install?
I don't particularly wan't to go with 2 TB drives as that will cost me more money.
I recall our R710 came with a H700 and we had to buy the PERC6 because the H700 doesn't support RAID 5. However a simple google search shows it does support RAID 5. Do you know if always did? I'm not sure why we got a PERC-6 if the H700 supported RAID-5.
theflash1932
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April 1st, 2014 11:00
Yes, the PERC H700.
Yes, it absolutely does support RAID 5, and it always did. The SAS 6/iR would have been an option in the R710, and it does not support RAID 5. The S300 supports RAID 5, but its performance is pretty poor. If it was indeed the H700 that you had received, I'd say you received some misinformation that led you to replace it with the PERC 6/i ... there is nothing the PERC 6 does that the H700 doesn't also do.
gregom
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April 1st, 2014 12:00
Thanks for all the info, you've been extremely helpful. Yeah I have a few cards we pulled from newer servers but none are a H700. Looks like we are going to have to buy one or stick with 2TB drives. I'll just figure out which is cheaper I guess...
pcmeiners
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April 1st, 2014 14:00
Ebay for the h700