Shane wrote: > On Mon, Aug 07, 2006 at 08:57:13PM +0100, Nix wrote: >> On 5 Aug 2006, David Greaves prattled cheerily: >>> As an example of the cons: I've just set up lvm2 over my raid5 and whilst >>> testing snapshots, the first thing that happened was a kernel BUG and an oops... >> I've been backing up using writable snapshots on LVM2 over RAID-5 for >> some time. No BUGs. > > Just performed some basic throughput tests using 4 SATA > disks in a raid5 array. The read performance on the > /dev/mdx device runs around 180mbps but if lvm is layered > over that, reads on the lv are around 130mbps. Not an > unsubstantial reduction. Check the readahead at various block levels blockdev --setra xxx I think I found the best throughput (for me) was with 0 readahead for /dev/hdX, 0 for /dev/mdX and lots for /dev/vg/lv > > I seem to recall patches to md floating around a couple > years back for partitioning of md devices. Are those still > available somewhere? man mdadm and see --auto... David -- - 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
