growing a raid 5 volume onto new physically larger disks

MossyUK

MossyUK

MossyUK

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I have a problem with a server - the box has 6 disk slots currently configured

2x 72gb RAID 1 mirror for OS
4x 146gb RAID 5 for data

or there abouts, the disk sizes may be off slightly.

Anyway, we have run out of space on the RAID5 set and need to increase the storage. What are my options for upgrading this disk set to bigger physical disks?

So far it has been suggested:

1. Go with an external NAS, using iSCSI for future growth across the site

2. Pull out the parity disk, replace it with a bigger physical disk, let it rebuild, slowly do this to the other three and then create a new volume in the increased space

3. Pull out the mirror OS disk, replace with large capacity disk, move the data from the RAID5 to the new disk, pull out the RAID5, replace with new disks, move data back

...

What other options are there? Thanks
 
Im assuming with the options you have looked at this is a server that you can down while you do this?

Depending on the server and raid card, you maybe able to pull teh partiy disk, put a bigger one in etc.

Depending on your growth requirements a SAN could be a good investment, howver to go to 300Gb disks which is the next ones up from the 146s i belive, are pricey.

If you wanted to do it that way, get an external HDD, format it to NTFS and dump out the data, pull the drives, put in bigger ones, new array and copy data back. Reason for the NTFS format is so you preserve your file permissions etc

Kimbie
 
Really depends on the make and model of server and more specifically the feature set of the controller, managed servers such as HP Proliant and Dell Poweredge allow you to do this kind of operation quite easily.
 
MossyUK said:
cheers for the replies - its a Dell Poweredge 2850, with a Perc 5i raid card.
Click to expand...

IIRC the controller won't use any bigger disks than the smallest one in the array.

IE 4*300GB and you put in 1TB disk would still only use 300GB of it.

So you'd need to copy the array to another offline storage device then drop the array in that server and put in new bigger disks then setup the array.

So options 2+3 wont work :)
 
Was going to say the same thing as Dangerous re: option 2 & 3, it's been a while since i did this, but could you not simply use your backup software, make a full backup of the current data set on the raid 5, down the server, insert new disks and set up using Perc/windows, then restore data from backup onto new raid set? That way you have a full backup of your data and also the original disks/raid set if something goes wrong.
 
Pull the disks to larger capacity units. Once each drive has done it's rebuild, move on to the next. once all drives have been done, you'll be able to extend the existing data volume on the fly for increased storage. This is the most efficient way to do what you're after and it can be done completely ONLINE

Ahh, sorry misread.

ONLY do this if you are prepared to replace ALL the disks, but it works, tried and tested many times.
 
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