Bill Davidsen wrote: > Eric Sandeen wrote: >> Hi, I hope this isn't a FAQ, I did do a little searching first... >> >> I'm looking at using a couple of large disks to mirror a system which >> currently has a few different filesystems; I'll use partitions on the >> disks to contain the different fileystems. >> >> It looks like I could mirror sda and sdb, and partition the resulting >> md_d0. Or, I could partition sda and sdb, and create mirrors md0, md1, >> etc from the partitions on the underlying disks. >> >> Is there any technical reason to choose one method vs the other? It >> seems to me that perhaps on a system with several active partitions from >> the same disk, partitioning a single large raid device might allow >> better read balancing? >> > > The reason for going with a partitioned raid is that rebuild after a > failure is easier. The reason for NOT going there at the moment is > discussed in another thread here, in the current kernel the partitions > are not started unless you have an initrd file to make that happen. The > last is performance, if you are using the partitions in different ways, > and some would benefit from performance while others (/boot comes to > mind) need to be simple and reliable, and have minimal requirements for > speed. Having partitions on the drive allows you to use different raid > levels across partitions, to best fit what you do with that data. Thanks. In my case I'd just have raid-1 on everything, so don't need that granulatiry... Another drawback in my particular case is that the Red Hat / Fedora tools don't seem to grok partitioned md, but I can fix that ;) Is there any merit to my notion about better read balancing across the entire disk if it's all one md device? Thanks, -Eric > I don't see any as compelling, there's no one best answer for everyone. > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
