Convert RAID 5 to RAID 1+0 on HP DL380 G4

[Taylan Aydinli]

Hi,

I have an HP DL380 G4 SCSI Model server running Windows Server 2008 R2 with Smart Array 6i controller in Embedded Slot.

Currently, the server has one logical drive in RAID 5 using all 6 drives.

I'm considering converting this RAID 5 volume to a RAID 1+0 configuration for performance considerations. I run the ACU GUI locally on the server. When I open the Migrate RAID/Stripe Size screen, I only see RAID 0 and RAID 5 as options for Fault Tolerance. I don't see RAID 1+0. What could be the reason for this?

Is it not possible to migrate a RAID 5 configuration to a RAID 1+0 configuration? Do I need to rebuild a new logical drive with RAID 1+0?

Also I'm curious: would it be wise to have 2 logical volumes instead of 1? Can anyone give me some info on the pros/cons of having only one logical volume versus having two?

Regards,

[TTr · Accepted solution]

First the size logistics about raid type migration. Your current raid5 has 5 data disks and 1 parity disk. The raid10 you are thinking of, will have 3 data disks mirrored. Does your data currently in raid5 fit into *three* disks?

Next, usually the raid controllers need a BBWC option to be able to do online array changes. It is not clearly stated on the 6i quickspecs but it is usually the case with smart array controllers.

http://h18000.www1.hp.com/products/quickspecs/12030_na/12030_na.html#Product%20Highlights

[Taylan Aydinli]

Hi,

there is almost no data in my raid 5 volume. I just got the server and I'm in the process of setting it up. So there shouldn't be any problem with capacity.

I'm not sure if the server has BBWC, I don't have physical access to the server ATM. Is there any way I can see if it has BBWC through some software?

And if the server does have BBWC, what could be the reason that ACU only gives me options for RAID 0 and RAID 5 in the Migration screen? Do I need to run ACU from the SmartStart CD or something?

Thanks

[TTr]

You can check the controller using ACU or ORCA or even physically opening the server and looking at the controller.

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c00217854/c00217854.pdf

[Taylan Aydinli]

I unfortunately don't have physical access to the server but assuming it does have BBWC, and knowing that there is only 20 Gb of data in the volume right now, how can I migrate this RAID 5 volume to a RAID 1+0 volume?

Can anyone give me any direction on this? The ACU GUI only gives me the option for RAID 0 or RAID 5 and I can't figure out why.

Thanks

[TTr]

>assuming it does have BBWC

> there is only 20 Gb of data in the volume

How big is the logical disk in the raid5 array? Not the files and not the OS partition, the logical disk! The array does not interact with the OS and does not take into account how big the OS partition is or how much data you have in it. All the array knows is that there is (are) logical disk(s) in its raid and the size of these disks MUST fit in the raid10 array.

So either way you need to get access to the server and check for BBWC or size of logical disks in the raid5 array.

[Taylan Aydinli]

Hi,

sorry it took a while for me to understand what you were trying to say:) There are 6 x 72Gb drives on the server. The size of the RAID 5 logical disk on the server is 342Gb.

When I build a RAID 1+0 array I'll only have around 200Gb of space in that logical volume.

So I'm guessing that's why the ACU won't let me migrate the RAID 5 to a RAID 1+0 configuration?

[TTr]

That's correct, the SA controller will need to convert raid5 stripes of size 342GB. Whether they contain OS partitions or data in them, it does not know and does not care. So this much space will NOT fit into the approximately 200GB of disk space that you get from a 6-disk raid10 array.

[Taylan Aydinli]

Thanks a lot for your help.

[Taylan Aydinli]

The RAID 5 virtual disk has 320Gb capacity. A RAID 1+0 configuration will only have ~200Gb, so a direct migration from RAID 5 to RAID 1+0 is impossible. Will have to delete the RAID 5 volume and create a new one with RAID 1+0.