Migrating from raid 5 to raid 1

[Jonny Barnes]

My customer has a Proliant server with an onboard 6i smart array controller. They currently have data on a 3 disk raid 5 set that they would like to migrate to a 2 disk mirror set. Is this possible to do? If not are there any other ways that this could be done without having to destroy the existing data and start again. My cutomer has mentioned things like adding another disk in, therefore having a 4 disk mirror set and then removing 2 drives but I don't think that this would work.

[Siikanen JukkaPekka]

Add 2 disks to array controller, put them on RAID1 an copy data from RAID5 to RAID1?

Or do you mean changing RAID5 to RAID1 "on the fly"? I think this is impossible.

-jukkis

[Michael Richter]

i suggest to create an Image and re-deploy it on the new Array

rg, mike

[Jonny Barnes]

Hi

My customer is talking about doing this on the fly - I don't know if this is possible?

[Brian_Murdoch · Accepted solution]

Jonny,

The quickspecs for the Smart Array 6i embedded controller state that online raid migration between any raid level is supported but doesn't elaborate on this.

http://h18000.www1.hp.com/products/quickspecs/12030_na/12030_na.HTML#Product Highlights

I know it can be a very lengthy process using ACU, so it may be easier to use GHOST for example and boot using a network floppy to copy the existing raid 5 image up to a network server, recreate the new raid 1 and then copy the image back again to the mirror. Of course going from raid 5 to raid 1 with the same physical disks will reduce the overall capacity so make sure that the saved image will actually fit before starting.

i.e. if you start with 3 X 72Gb disks in raid 5, the overall capacity is 144Gb (1 lost to parity). If you then use 2 X 72Gb in raid 1, the overall capacity is 72Gb. If your saved image from the raid 5 exceeds 72Gb in size you'll have problems. Larger physical disks would be needed to create a large enough mirror to hold the original image (say 2 X 146Gb disks instead). Its probably easier as suggested earlier to add two more disks in a raid 1 and ghost locally from raid 5 to raid 1 and then remove the raid 5 disks. That way you will still have the original raid 5 disks untouched if things go bad.

The following ACU reference guides may help.

http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual〈=en&cc=us&docIndexId=179111&taskId=101&prodTypeId=18964&prodSeriesId=468780

Regards,

Brian

[Jonny Barnes]

Hi Brian

Many thanks for that. I will pass on teh information.

Cheers.

Jonny