How to increase RAID5 Array disk space without adding drives

Question

I'm beginning to run low on disk space on my Dell PowerEdge 2400 server. It's running MS Server 2003 with two mirrored 18gb drives for the O/S and four 9gb drives configured for RAID5 holding data only. Since all my drive slots are full I'm wondering the best way to increase the physical disk size of the RAID5 space. My thought is to, one at a time, remove a drive and replace it with a larger drive, wait for it to regenerate, then repeat the process until all four drives were physically upgraded. I would then use the Dell Array Manager to increase the size of the array. Does this seem like a prudent procedure?

Thanks - Steve

bilbus · Answer

thats the way

SRSnure · Answer

As mentioned previously I currently have four 9.0gb hard drives in my RAID-5 array divided into three logical drives whose total capacity is about 27gb.  I've acquired four 36.7gb hard drives to replace the existing 9.0gb drives.  During the upgrade I'm thinking that I would prefer to change the configuration of the RAID from four to three drives (giving me 73.4gb of space) and have the fourth as an online hot spare for this array.  Can this be done once the new drives are installed?    Thanks - Steve

OfficeLinebacke · Answer

Hi. I am about to do something similar. As far as the hot swap, I think what you want to do is first get everything except the hot swap installed and configured. Then, just add the final disk and then select it and make it the hot swap.

Also, great idea on how to replace a set of smaller disks with larger ones. I am faced with the prospect of backing everything up to tape, replacing four drives with four bigger ones, setting up the new array, and then restoring the data. This solution makes much more sense. :) I just have to make sure it's possible on a PE 1600SC with PERC 4/SC.

If anyone happens to know if this is possible or not, please reply.

Thanks!

Dev Mgr · Answer

One note: be sure to have a backup when making changes like this on a system that's important to you.

I'm not sure the raid container will grow after you swap all the drives. The raid controller may have the extra space, but this space could be available for a new container, which would mean a new virtual harddrive to show in disk management. This would defeat the purpose of what you're trying to do.

OfficeLinebacke · Answer

Yeah, I think it may end up in a result that's not exactly what we're looking for. Once the new drives are in, the best we could probably do is another virtual drive and another drive letter. We really just want to make C: and D: bigger.

As a sort of side issue, is there something specific to the architecture of some RAID controllers that limits the number of internal drives to 4? I see that one can buy 68 pin SCSI 320 ribbons with 6 drops (not from Dell). But someone told me that with a PERC 4/SC in a PE 1600SC, you can only have up to 4 internal drives due to some limitation in the hardware.

Thanks, and yes, we do nightly tape backups, so I am trying to figure out any way to avoid restoring from tape (even to the point of considering buying an IDE HD just for this).

pcmeiners · Answer

'During the upgrade I'm thinking that I would prefer to change the configuration of the RAID from four to three drives (giving me 73.4gb of space)' Raid 5 increases in throughput for each drive added to an array, you do not want to decrease from 4 to 3 drives.   You should get a significant speed increase going to the 36 gig drives, as the 9 gig drives were very slow.   Acronis Disk Director will allow you to expand the present partitions with the new unallocated space    Message Edited by pcmeiners on 07-25-2007 11:04 AM

alasdhair · Answer

I downloaded the trial version of Acronis and it does not see the additional free space on my RAID-5 disks.  I had 3x36GB disks in RAID-5 then replaced them with 3x73GB and want to increase my C: and D: partitions to absorb the remaining space.  But Acronis does not see the additional space and options within Acronis only seem to want to snarf space from other partitions to increase the size of any one.  Dell System Manager sees the additional free space but offers no ways to use it (that I can see).   What I want to do is increase C: from 10GB to 20GB and D: from 57GB to use the remaining free space.   Can anyone offer any advice as to the process I should follow?   Thanks, Alasdhair

PowerEdge HDD/SCSI/RAID

How to increase RAID5 Array disk space without adding drives

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