Hi all,

some people use raid1 for swap partition, others raid0, others without any raid (simply adding the two or more partition "linux swap" into /etc/fstab).

What is the best method?
Thanks

Hello,

first of I apologize if I'll mix up the raid0 and raid1, raid0 mirroring and raid1 "bigger disk space" with 2 or more hard disks.

Having SWAP on raid0 which I think is mirroring makes no sense to me. You have a SWAP partition on one disk and a clone of it on the other. So if one disk goes the other stays intact and the swap partition is saved, which doesn't make sense because you're gonna have to shutdown and take the busted disk out.

On the other hand raid1 make no sense to me either, because raid1 works in such way that it combines two or more disks, let's say both are 120GB and when you put them in a raid1 you have 240GB, but recording onto a raid1 is done in a meaning something gets written on one disk, something on other, not in means of files but in means of bits of files.
So why put SWAP on a raid1 field? I think it's better of to just create a separate partition on one of the hard disks and have swap located there.

Just my personal opinion.

Regards

The method recommended by anyone involved with the kernel is (I believe) to just swapon a partition on each drive, and this will perform it's own "raid" between them without any extra code being involved. So they say that you just let Linux handle it all, which seems fair enough to me seeing as they wrote the code, and it also means that all you need is a swap partition on each raid'd drive, which you're probably going to do anyway. You won't get any speed advantages by doing it any other way, because the swap code already "raids" multiple swapspaces automatically.

Tux-Slack did have the RAIDs reversed, RAID0 is a combination of drives, RAID1 is a mirror. Neither is needed with swap. Having a swap space on each disk is fine, combining them into some form of RAID is a waste of processor power, because you get nothing for the combination. As mentioned above, the kernel treats one large swap partition the same as it treats multiple small partitions. So you lose processing to make a RAID swap partition, and gain nothing for it.

Peace,
JimBass

I knew it that I was going to write them wrong, thank you for the correction.