> Andreas Dilger <adilger@turbolabs.com> writes: > > > Swap is a bad move, since you can just add multiple swap spaces with the > > same priority (if you so choose) and it will do the striping for you. > > Likewise, you could put each of the above trees on their own drive and > > you would probably get better overall performance than striping. > > This suggestion has always bothered me. Yes, if all you care about > performance, setting up swap this way works fine. However, for every > drive you add you increase the likelyhood that you're system will fail > due to a drive failure (what happens when one of the swap slices > suddenly dissapears?). For this situation, we are considering drives failing entirely. (If you consider grown defect bad blocks appearing, then it is probably no more likely for a bad block to appear inside 1G of disk spread across two disks than it is for a bad block to appear inside 1G of disk on one disk.) Swap devices only contain volatile data anyway. I wouldn't mind losing the contents of my swap device. The machine will probably crash. It's the same as if the machine went down through a power outage. Not a big problem. Assuming only the swap device failed, I could just re-boot and run with a bit less swap space. If the drive fails, I lose the contents of any filesystems on the same drive. Much more significant. The fact that the machine went down because the swap device failed pales into insignificance, because now all the data has disappeared. No-one can do any work until we have replaces disk(s), sorted out the filesystems, restored from backups etc. If the swap had been configured on a different disk, we would have the marginal benefit of the machine probably not crashing, but the filesystems on the failed disk would still have disappeared, and we would still have the same problem. So I spread my swap over all the fast disks, by putting them directly on to disk paritions and setting the same priority value. Regards, Bill -- William H. Blunn - bill@tao-group.com - Developer Support Tao 62/63 Suttons Business Park, Earley, READING, RG6 1AZ, United Kingdom Tel: +44 118 901 2999 - Fax: +44 118 901 2963 - http://tao-group.com/ _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
