Nope. :-) root@yupa:~# dd if=/dev/md1 of=/dev/null bs=64k count=65536 65536+0 records in 65536+0 records out 4294967296 bytes (4.3 GB) copied, 10.1625 s, 423 MB/s root@yupa:~# dd if=/dev/mapper/yupa of=/dev/null bs=64k count=65536 65536+0 records in 65536+0 records out 4294967296 bytes (4.3 GB) copied, 35.2504 s, 122 MB/s On Sat, May 14, 2011 at 11:30 AM, Milan Broz <mbroz@xxxxxxxxxx> wrote: > On 05/14/2011 04:36 PM, Kyle Rose wrote: >> For the past week I've been trying to figure out why my >> dm-crypt-on-RAID6 performance is so terrible. To wit: >> >> root@yupa:/source# hdparm -t /dev/md1 >> >> /dev/md1: <---the RAID 6 block device >> ÂTiming buffered disk reads: 1262 MB in Â3.00 seconds = 420.19 MB/sec >> >> root@yupa:/source# hdparm -t /dev/mapper/yupa >> >> /dev/mapper/yupa: <---the dm-crypt device with /dev/md1 as the underlying store >> ÂTiming buffered disk reads: 370 MB in Â3.00 seconds = 123.26 MB/sec > > IIRC hdparm is doing direct io of size 2MB. > > Can you try do the same but with dd (just dd from device without direct mode). > like "dd if=/dev/md1 of=/dev/null bs=64k count=4096" > > Gives it better throughput now? (on 2.6.38 and above) > > Milan > _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
