On 22/09/2009 14:07, Majed B. wrote:
When I first put up a storage box, it was built out of 4x 500GB disks, later on, I expanded to 1TB disks. What I did was partition the 1TB disks into 2x 500GB partitions, then create 2 RAID arrays: Each array out of partitions: md0: sda1, sdb1, sdc1, ...etc. md1: sda2, sdb2, sdc2, ...etc. All of those below LVM. This worked for a while, but when more 1TB disks started making way into the array, performance dropped because the disk had to read from 2 partitions on the same disk, and even worse: When a disk fail, both arrays were affected, and things only got nastier and worse with time.
Sorry, I don't quite see what you mean. Sure, if half your drives are 500GB and half are 1TB, and you therefore have 2 arrays on the 1TB drives, with the arrays as PVs for LVM, and one filesystem over the lot, you're going to get twice as many read/write ops on the larger drives, but you'd get that just concatenating the drives with JBOD. I wasn't suggesting you let LVM stripe across the arrays, though - that would be performance suicide.
I would not recommend that you create arrays of partitions that rely on each other.
Again I don't see what you mean by "rely on each other", they're just PVs to LVM.
Cheers, John. -- 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
