On Thu, Aug 05, 2010 at 11:39:43AM -0400, Chris Mason wrote: > On Thu, Aug 05, 2010 at 05:35:19PM +0200, Dominik Brodowski wrote: > > On Thu, Aug 05, 2010 at 07:32:40AM -0400, Chris Mason wrote: > > > But, I'm surprised your drive is doing 8K dio reads at 16MB/s, that > > > seems a little high. > > > > Well, that's what it does: > > > > # $ dd if=/dev/mapper/vg0-home_crypt of=/dev/zero iflag=direct bs=8k count=131072 seek=131072 > > # 131072+0 records in > > # 131072+0 records out > > # 1073741824 bytes (1.1 GB) copied, 62.0177 s, 17.3 MB/s > > Can I ask you to do the test directly to the real honest to goodness > drive? If it were an SSD I'd be less surprised, but then the extra > submits shouldn't hurt the ssd that much either. >From lower the chain up to the device: # LANG=EN dd if=/dev/mapper/vg0-root_crypt of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 63.1217 s, 17.0 MB/s # LANG=EN dd if=/dev/mapper/vg0-root of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 43.2335 s, 24.8 MB/s # LANG=EN dd if=/dev/sda5 of=/dev/zero bs=8k count=131072 seek=393300 iflag=direct 131072+0 records in 131072+0 records out 1073741824 bytes (1.1 GB) copied, 42.0868 s, 25.5 MB/s Best, Dominik -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
