Upgrading the drives of a RAID 5 array. How is it done?

[Jeff7]

I've got a RAID 5 setup here, courtesy of a Promise SX4000, and I'm thinking about upgrading it for three reasons:
1) I'm losing faith in Hitachi's drives. I thought that the click-of-death was restricted to the 60GXP and 75GXP's. Then I had a 120GXP die of a serious head crash. "Ok, that's not the click of death, it's an unrelated problem." I RMA'd it, and got a larger 180GXP. It's now clicking, and may have to be declared dead, which will not be a good thing, as it's not my data or my drive anymore.
2) One of the drives' SMART is reporting Reallocated Sector Events. During a chkdsk, at 1% through the surface check, I got a few spikes in the Raw Read Error counts. So this thing might be developing bad sectors.
3) I can use more space


I'm eyeing some Seagate drives now. But how do I upgrade the RAID 5 array? The results at Google indicate that the new drives will be integrated into the array automatically by rebuilding it, replacing one drive at a time. However, this will truncate the drives' sizes to 160GB each, the size of the current drives. This would leave a lot of unallocated space. Could I use some partition manager software to resize the existing partitions to fit the unallocated space? Or would this cause some kind of weird partition fragmentation?

I don't think that I can just copy the data off the old drives, wipe the old array, and stick the new drives in, as there is more storage space in this one PC than there is in the rest of the house.

 

[Staz]

I am not sure if this is as specific as you want, but you should be able to just pull one of the drives, replace it with a brand new one of a larger size, go into your RAID setup program and tell it to rebuild the array using the new drive. Do this for each drive and you should be good to go.

 

[Jeff7]

I'm eyeing some Seagate drives now. But how do I upgrade the RAID 5 array? The results at Google indicate that the new drives will be integrated into the array automatically by rebuilding it, replacing one drive at a time. However, this will truncate the drives' sizes to 160GB each, the size of the current drives. This would leave a lot of unallocated space. Could I use some partition manager software to resize the existing partitions to fit the unallocated space? Or would this cause some kind of weird partition fragmentation?

 

[Vegito]

yeah, ie

u got 3 60gb drives , in raid 5, it will be 120gb.. you add another 60

your raid will be 180gb but ur parition still remains at 120gb.. with 60gb unallocated.


Your best bet, ghost the primary data drive to an image, create new raid disk, restore the image and it'll be the full 180 gb.. using partition magic would work but theres a chance it'll die.. its better if you use ghost and it'll have at least a backup copy on image

 

[Jeff7]

Originally posted by: forcesho
yeah, ie

u got 3 60gb drives , in raid 5, it will be 120gb.. you add another 60

your raid will be 180gb but ur parition still remains at 120gb.. with 60gb unallocated.


Your best bet, ghost the primary data drive to an image, create new raid disk, restore the image and it'll be the full 180 gb.. using partition magic would work but theres a chance it'll die.. its better if you use ghost and it'll have at least a backup copy on image

As I interpret this, you mean, back up the entire array to an image elsewhere, and then purge the array? If that's correct, I've still got the problem that I can't store the image anywhere else. It'd take up a LOT of DVD-RW's if I go that route, and I don't have enough storage space on my entire network to store the contents of this one PC.

 

[Vegito]

yeah.. thats pretty much what the emc wanted us to upgrade our array also.. dump it to a bigger one and delete the old one.. i was like wtf, for 500k an emc san array should be able to expand this by itself..

if you were to use partition magic, better throw the pc on a ups in case you lose power or anything else.. but pretty much it usually works w/o problem.. but for something that large.. i wouldn't risk it.. maybe if you back up some of the more important file just in case

 

[Robor]

No matter how you try it make sure you backup anything important before you do. Large IDE drives are cheap these days. Heck, you might even know someone who's got a drive lying around not being used.

 

[Matthias99]

Originally posted by: Jeff7

Originally posted by: forcesho
yeah, ie

u got 3 60gb drives , in raid 5, it will be 120gb.. you add another 60

your raid will be 180gb but ur parition still remains at 120gb.. with 60gb unallocated.


Your best bet, ghost the primary data drive to an image, create new raid disk, restore the image and it'll be the full 180 gb.. using partition magic would work but theres a chance it'll die.. its better if you use ghost and it'll have at least a backup copy on image

As I interpret this, you mean, back up the entire array to an image elsewhere, and then purge the array? If that's correct, I've still got the problem that I can't store the image anywhere else. It'd take up a LOT of DVD-RW's if I go that route, and I don't have enough storage space on my entire network to store the contents of this one PC.

*Some* RAID5 controllers can expand the array without requiring you to move it (although you might have to make the new space a separate partition from the old one). However, this depends on the RAID controller you have, which you conveniently didn't mention.

 

[Jeff7]

No matter how you try it make sure you backup anything important before you do. Large IDE drives are cheap these days. Heck, you might even know someone who's got a drive lying around not being used.

"Cheap" is relative. I can't just go and buy 5 MORE drives, in addition to the 5 I'd already be buying, and just use them for temporary storage.



I updated the original posting; I'm using a Promise SX4000. I had checked the manual for that, but I just thought to check the manual for the Promise Array Management software. There's a section in there for....you'd never guess it, "Expanding the Array."

Expanding an array increases the array capacity without affecting data
availability. You can expand an existing array by adding one or more free disk
drives to the array using the Expand Array function.


? With most operating systems, expanding an array will
require you to partition the added space with a new drive
letter. In effect, you will end up with two arrays.

So it looks like I'll have to finally buy some partitioning software, and probably some imaging software while I'm at it, from Acronis.
Or else just live with another drive letter.
.
.
.
.

You know, I am actually thinking it through, and I guess that I'd be left with 5 drives after the array finishes its migration to the new drives, one at a time. I could hook them up as external USB drives, and transfer the data off that way. Sucks that I can't image the OS....ooh, cool. Norton Ghost doesn't support RAID. Acronis True Image: "All levels of IDE and SCSI RAID controllers supported."
Well I thank you all for the suggestions; looks like I should have read the manual(s) thoroughly. Oops.
Time to mull over the decision to buy 5 new drives.....$$$$$.