Some quick Bonnie numbers run on the RAID-6 code. The machine has one
P4/1.8 CPU and 512 MB RAM; the file size was 1024 MB and the filesystem a
"virgin" ext3. Each partition was 10 GB; each disk is a 40 GB ATA/100
drive. The stripe size was 256 KB.
I suspect RAID-6 write performance should be possible to improve;
currently it doesn't do read-modify-write for the syndrome drives, for
example.
RAID-6 across 6 disks:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1024 4579 95.7 21733 8.4 10993 4.1 4483 93.8 28751 6.5 331.5 3.0
RAID-5 across 5 disks (same capacity):
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1024 4622 96.4 56730 23.5 17249 6.4 4651 97.4 29761 6.1 322.4 2.8
RAID-5 across 6 disks:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1024 4597 96.0 28771 11.2 12890 4.7 4558 95.4 29133 6.5 344.3 3.0
Single disk:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
1024 4738 98.8 33435 14.2 16157 5.9 4718 97.7 34268 4.3 151.3 0.7
--
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
If you send me mail in HTML format I will assume it's spam.
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64
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