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GordonRaeFlag for Afghanistan

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How to increase RAID hard drive capacity

Dear Experts,

As I have never been here before, please check my thoughts, and tell me if I am going to fall down.

Dell 2850 with 3 x 73gb drives (10,000RPM).... We are running out of space.

Am I right in this;

Replace each drive with 2TB sata 7200's wait at least 3 days between each to allow "rebuild of disk"

I should then have a RAID Array showing the same space, but with Acronis Disk Director for Servers, Re-partition the drives to allow usage of the extra space.

How close am I? The Server works perfectly well and has expensive SQL licences. Like to extend it's lifetime.
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Lee W, MVP
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Not quite, mixing SAS and SATA drives is likely not supported.

You can replace the SAS drives (assuming they are, in fact, SAS drives and NOT traditional SCSI) with larger drives.  Then, I don't think you'd have to wait 3 days... probably over night would do.  The Dell utilities you should have installed to manage and monitor the RAID array should tell you when the rebuild is complete.

Once the rebuild completes, you would still have to enlarge the CONTAINER that the RAID controller defines the RAID array with (again, using the Dell Utility, assuming the controller supports this).  

Once the container is expanded, the OS should see the extra space in Disk Management as unpartitioned/unallocated disk space.  THEN you can use Acronis or even DiskPart (if you only need to extend the data drive).

Why are you concerned about SQL licenses?  Are they OEM?  If not, you can just move SQL to a new server.


(The Dell utility I'm referring to - if they haven't changed the name - is the Dell Open Manage Array Manager).
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ASKER

Thanks Lee, get the drift with sas / sata not mixing, of course it wont, silly me.
Thanks for the instructions, seems straightforward.
As for keeping licences, thats just part of it, having larger drives would save a lot of work replacing it, as I said, it works fine.
I'll now go and source larger drives, my goodnes, they are expensive!
GordonRae, your desired technique can result in 100% data loss in event a drive fails during the rebuild, and partial data loss in event of a bad block.  The right way is to create a full bare metal backup, with something like Acronics or Ghost; then build a new Array with the replacement disks; then restore onto the new array.
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PowerEdgeTech
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No, it isn't as easy as that. First of all, what types of drives are you currently using? are they SCSI, SATA or SAS? I don't know what specific hardware your server comes with, that's why I'm asking. If you are currently using SCSI drives, you'll have to change the RAID controller if you want to use SATA or SAS drives... This would also mean you don't have any easy way to increase the space. A backup, then restore would be simplest, or if you can keep the old drives and add the new ones with a new controller, you can just create an additional array.

If it is already SATA or SAS, you would first have to make sure the new drives are compatible with the controller. If you buy the new drives through DELL that should be no problem. If on the other hand you want to keep things cheap and want to buy drives that aren't supplied by DELL, you risk that they won't work.

A further issue you will run into if you are going to use 3 2TB drives is that the boot drive of Windows, if it is using the MBR system (which is the default), you'll be limited to a toatl of 2TB on that volume. For more than 2TB you need a GPT partition table, and I don't think you can change that on an installed system:

http://en.wikipedia.org/wiki/GUID_Partition_Table

Lastly, if you can get around the above obstacles, before being able to increase partition sizes using acronis or any other partition manipulating tool, you'd have to expand the array (after all new HD's have finished syncing) so the new space gets available. You'd have to do that via the RAID controller's utilities, but it would have to have that function in the first place. So you'd first have to check the controller's manual whether that is available. Only after that will acronis or whatecer be able to see the extra space.
The drives are       SCSI 80 PIN (SCA)  (Just found out).

This option looks good;
2) Simply add additional 73GB drives, Reconfigure 3-disk RAID 5 to 6-disk RAID 5, which will give you around a 365GB array.  You can then use your partitioning software to resize your partitions.
Qusestion for pwerEdgeTech: of the six bays, three have the 73gb's but I have also used a drive bay for back ups. Can I expand from 3 to 5 disks OK?
Rindi - see my comment about the 2850 - it only take SCSI drives, and there is no kit to adapt for SAS/SATA.  I've done this hundreds of times on a 2850.  Not only is it possible - and available by design - it really is that simple if you are familiar with the hardware.

Gordon - yes, you can Reconfigure RAID 5 from three to four, five, six disks (or however many you have available) just fine.  As with any major system change (reconfiguring, changing partitions, etc.), make sure you have a backup.
Are you considering using RAID-5 + a spare?

If so if your RAID controller will do it, Do Raid-6 as it gives you a more resilient result.
The PERC 4's available in the PE 2850 do NOT support RAID 6.
OK so do RAID-5 plus a spare to minimise the risk, or maybe RAID-10

Going from 3*73GB (ie 146GB useable assuming you are using RAID-5) to 4 * 300GB@10K will still give you 600GB or nearly 5* what you have now.

Going for the big disks that run at only 7200 you might find gives you performance issues, or make  the system seem like its going real slow!
Note that if you choose to Reconfigure, you cannot go from RAID 5 to RAID 10 on the PERC's ... you would need to go the route of backup, create RAID 10, restore to implement a RAID 10, where you can Reconfigure RAID 5's by adding drives to it on the fly.
Thank you.