-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have a raid5 array /dev/md1, being used as the pv of an LVM Volume Group. I have a very peculiar problem with the array: Writes to it happen at 40MB/sec or so. But *reads* from it happen at 10MB/sec. This, given how raid5 works, is a bit weird. dd if=/dev/md1 of=/disks/raid_backup/test_speed bs=10M gives 21MB/sec, which is, while not good, not bad for dd. while: dd if=/dev/mapper/system-raid_lvm of=/disks/raid_backup/test_speed bs=10M 4+0 records in 3+0 records out 31457280 bytes (31 MB) copied, 8.75426 seconds, 3.6 MB/s which is obviously bogus. dd if=/dev/sdg of=/disks/raid_lvm/test.speed bs=10M 24+0 records in 23+0 records out 241172480 bytes (241 MB) copied, 11.6211 seconds, 20.8 MB/s So, writes to the system VG happen at least 4xfaster than reads. This to me seems insane. Note that: pvs PV VG Fmt Attr PSize PFree /dev/md0 backup lvm2 a- 1.46T 159.20G /dev/md1 system lvm2 a- 1.82T 63.04G /disks/raid_backup/ is actually the backup VG. /disks/raid_lvm/ is actually the system VG. Any ideas on why this happens would be very appreciated. mickg@xxxxxxxxx -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (MingW32) iD8DBQFGI7WOoRaxTYdM/EwRAqWnAKDadOnzfPuzzoMILAsaddWwdK2XIgCgmGzm dUlR7OPxasuKa1JwtUoR60E= =8Vtw -----END PGP SIGNATURE----- - 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
