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Daryl PontingFlag for United Kingdom of Great Britain and Northern Ireland

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How to migrate RAID 1 to RAID 1 with bigger disks?

Hi experts,

I have a DL360 G5 which currently has two 73GB disks in it configured as a RAID1.  I want to 'migrate' this to a RAID1 using 146GB disks.  The server is running Exchange 2003.  It's a G5 with six disk slots so I can put the new disks in alongside the current disks.

Is there any way to migrate or copy the current RAID1 to a new RAID1 using the new disks?  I don't know if the standard RAID card has two channels in it to create two raids?  Any ideas on how to tackle this would be greatly appreciated.

regards,
Daryl.
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Randy_Bojangles
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Thanks for the reply.

I was wondering if I could do something like that but I wasn't sure how the raid would work with different size disks.

When I remove one 72gb disk and put a 146gb disk in, I'd expect the 'rebuilt' raid to be using just 72gb of space on the 146gb disk.  So when I put the other 146gb disk in, wouldn't it rebuild and still just use 72gb of space?  so I'd have two 146gb disks, but the raid would only be 72GB?  How would it extend to 146GB?

I hope that makes sense.
Makes perfect sense and that is how it works until the second rebuild finishes

then, as noted above, you'll "magically" have an extra 72GB of space on the RAID

You can then either make this a separayte logical drive and letter that Windows sees or use diskpart to join them together to give you all of the space on your current volume(s) on the RAID 1
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Thanks for that, that's a really useful document.

This may be difficult to answer, but can you give a rough idea on how long a rebuild will take when I change one of the disks?  The server will be doing pretty much nothing at the weekend (when I plan to do it) so I can set the rebuild and extend priority to high, it currently has about 40GB of data on it and as you know, it's a 72GB RAID.  The link you provided says that you're looking at 15 mins per gigabyte when extending the RAID so I'm looking at 18 hours to extend it.  Am I looking at 18 hours for the rebuild (seems like a long time) or something like 2-3 hours or so for each rebuild?  some rough ideas would be useful so I can plan the weekend.

many thanks for all your help.
I've never really come up with a reliable benchmark when I've done these as all sorts of factors (rebuild priority setting, server usage, used disk space, cache, disk speed (both transfer and rpm)) have an impact

You should be able to see each disk be done in a few hours each I'd say though
Should take no longer than 1.5 - 2 hours for one drive. Do one after the other so you may need up to 3 - 4 hours to complete. The drive expansion is a separate process after the drives swapping. The entire process including drive expansion may take you up to 10 hours as max. I would schedule a Saturday for this task and should be done on the next day so you can get it ready for Monday. That what it normally takes when I perform the same task.

K
That's great.  Thank you both for your help.
Not a problem - please report back to let us know if (when) all goes well :-)
Hi Guys,

just to let you know the upgrade went perfectly, no problems at all.  

Thanks again for your help,
Daryl.