Question about RAID

R00KIE · 2012-01-29 14:41:19

I'm currently planning on joining 2 external hard disks I use for backup in a RAID1 array. Until now I used to copy the data to one of the disks and then rsync it to the other, but that is a bit of a hassle and prone to errors.

Not having dealt much with RAID before I've been "playing" with mdadm in preparation to convert the 2 external hard disks into one array and I have a doubt. Currently I use arch on my machines and take care of a few other machines with CentOS 5 so I have no idea of what other distros do when dealing with raid.

CentOS has a cron job that runs every week that iterates over all RAID arrays and tells them to check for problems (something on the lines of 'echo "check" > /sys/block/md?/md/sync_action'), from what I've seen on google searches this seems to be a good idea to check for bit rot or the appearance of bad sectors, however there is no mention in our wiki pages [1,2] about it. As with all things internet, some information comes with an expiry date and I was wondering if not mentioning periodic check/repair of RAID is an omission on our wiki or not needed anymore.

[1] https://wiki.archlinux.org/index.php/RAID
[2] https://wiki.archlinux.org/index.php/So … ID_and_LVM

Edit:
Forgot to add the references.

Last edited by R00KIE (2012-01-29 14:42:02)

graysky · 2012-01-29 14:50:03

btrfs might be a better way to go.

http://www.phoronix.com/scan.php?page=n … px=MTA0ODU

R00KIE · 2012-01-29 15:03:29

Yes, but it is still under a lot of development, even the man page says:

Btrfs filesystem is currently under heavy development, and not suitable for any uses other than benchmarking and review. Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for further details.

I don't mind being a bit of a guinea pig, I'm all for testing most new and shinny things (I wouldn't be using Arch if I didn't like such things would I ) but not with data that I cannot recreate (photos, school reports, ongoing thesis work, ....).

I know that recently a fsck/repair utility was released (or is going to be released very shortly) but for now I'd like to use something I know that works. I don't have much experience with either raid or btrfs but I've already seen raid do its magic first hand and so far ext4 (which is what I'm using on my machine and what I'm planning to use) hasn't eaten any of my data even with unclean shutdowns.

I may transition to btrfs later on when I run out of space and buy new disks (btrfs really looks very good), but for now I'm planning to stick with tried and tested

Arch Linux

#1 2012-01-29 14:41:19

Question about RAID

#2 2012-01-29 14:50:03

Re: Question about RAID

#3 2012-01-29 15:03:29

Re: Question about RAID

Board footer