Software Raid-0 for / Partition?

Message

nero37 · Post by **nero37** » Mon Sep 24, 2007 10:41 am

hi, im just after getting a new notebook and it has 2 x 200GB hds and am preparing to install gentoo. since i have 2 hds i was thinking about creating a ~30GB partition on each hd and using these to create software raid-0 array for my / partition.

Do you think this is a good/crazy/stupid idea?

pdr · Post by **pdr** » Mon Sep 24, 2007 10:56 am

As long as the cost (higher chance of unrecoverable failure) is worth the benefit (faster access) to you, and that you either like doing new installs or do regular backups

which you should do even without raid-0, then I don't seen why not. I run raid-1 (with backups) on my workstation personally..

nero37 · Post by **nero37** » Mon Sep 24, 2007 11:43 am

thanks for the info, im still kinda torn over it as iv had a hd die on me before.

Since it is software based, would i have to install gentoo to a normal patition and then create the raid array and copy the contains accross or could i use the live cd to create it before the install?

Thanks

Akkara · Post by **Akkara** » Mon Sep 24, 2007 12:00 pm

I haven't yet set up a raid myself (but I've been thinking about it) so this might not be polished accurate advice -

I'd probably go with two partitions: a smaller raid-1 and a larger raid-0.

Make a 10-15GB raid-1 and put root on that, so that even if a disk fails entirely (or you pull it out for whatever reason) you still have something that can boot and look at the remains with. When reading, is a raid-1 about as fast as a raid-0? (at least, it seems it could be?) Root doesn't change as often so write performance might not be as much of a issue.

Then /home, /tmp, /var/tmp can go on a raid-0 (and you can use mount -o bind so you don't actually have to make 2-3 separate partitions for those).

Or alternatively, you can make a larger raid-1'ed root and put /home there, then have a /workarea or something like that with a large raid-0. Larger files that aren't as important can go there, and smaller files that are more important whose loss is more critical can go on the raid-1.

the_mk · Post by **the_mk** » Mon Sep 24, 2007 12:52 pm

I think that if you have very important data on your notebook, you can plan dailies backup for these (on secure disks), and weekly backups for system files (on same disk), maybe in the end of the day, because with notebook you can damage hd accidentaly (ex: crashes), so you can make a full raid-0 system, expecially if you have got two slow hard disks (5400rpm)

Mad Merlin · Post by **Mad Merlin** » Tue Sep 25, 2007 1:59 pm

All hard drives die eventually, it's just a matter of time.

You should also consider that RAID 0 will degrade your seek times (but improve your sequential read/write times). For 5400 RPM laptop drives, the seek time degradation will be magnified. If you're normally working with lots of small files instead of a few big files, you'll probably find that RAID 0 isn't a big improvement (if an improvement at all).

pdr · Post by **pdr** » Sat Sep 29, 2007 6:56 pm

Also, I use rsnapshot (it is in portage) to back up my systems to an external eSATA/USB hard drive (eSATA on the workstation, USB on the server). Because it is using rsync, my server for example backed up in 2-3 minutes last time (not a lot changes on the server). The reason I like rsnapshot is that I don't have a LOT of data changing between backups, and while it is incremental, it is also a direct image (well, with hard links), not tar'd, gzip'd, etc; restore is as easy as copying, and it is easier to restore an individual file than any other method I've used.

The Vantec eSATA/USB external hard drive case I use is $35 at newegg.com, and if you are only going to use 60GB on the laptop for linux, you could for example pick up a 160GB WD hard drive for $70 (this can vary widely - there are constantly deals on <500GB drives)