Is it _safe_ to extend a raid5 (software)?

sen · 2007-08-12 21:29:00

Hi, currently the raid5 on my fileserver uses 4 hdds and I'm planning to add one more drive. There is just one problem... I can't backup all files that are stored in the raid (over 1TB)!
I really don't want to lose any of these files so I want to ask if someone, who has experience with raid-setups, could give me some help.

the current setup:
- Linux Software Raid5
- 4x500GB sata
- one big xfs partition (just for storage, the fileserver has a separate system drive)

what I'm planning to do:
- install another 500GB hdd
- partition the drive like the other 4
- unmounting the raid

mdadm --add /dev/mdX /dev/sX#

mdadm --grow /dev/mdX --raid-devices=5

- mounting the raid again (sounds weird but it seems an xfs partition must be mounted to resize it)

xfs_growfs /mnt/raid

I've never resized a raid and an xfs partition before, so it would be really nice if someone could give me some tipps!
Well, I cant say why but I have a bad feeling about doing this without a complete backup... do you think this is safe?

Last edited by sen (2007-08-12 21:31:09)

cactus · 2007-08-12 21:45:03

If you are interested (and have a bit of storage space), you could try doing a "dry run" in vmware to see if you have any problems performing the steps.
Set up a vmware instance with a few drives and then try adding another one.

I don't know if there is a limit on the number of disk drives that vmware can emulate though..but it might be worth trying if nobody response with a 'I have done it and it works' type experience.

sen · 2007-08-12 22:07:45

Heh, good idea! If no one replies I'll do that and post the result

Arch Linux

#1 2007-08-12 21:29:00

Is it _safe_ to extend a raid5 (software)?

#2 2007-08-12 21:45:03

Re: Is it _safe_ to extend a raid5 (software)?

#3 2007-08-12 22:07:45

Re: Is it _safe_ to extend a raid5 (software)?

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