[Beowulf] bad bonnie++ in 14-drive RAID 10

[Joe Landman]

Eugen Leitl wrote:
> Below bonnie++ stats are pretty bad for a RAID 10 of 14 SATA
> drives (WD RE4, 2 TByte), right?

Well, we'd suggest using fio rather than bonnie++, but I'll save that 
for a post somewhere else.

> 
> [oracle at localhost data]$ bonnie++ -d /data/blah

[...]

> Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
>                     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
> Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
> localhost.lo 47320M 82406  99 466201  46 124266  17 73482  96 541644  33 415.4   0
>                     ------Sequential Create------ --------Random Create--------
>                     -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
>               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
>                  16  5488   4 +++++ +++  4292   0  3883   3 +++++ +++  2580   1
> localhost.localdomain,47320M,82406,99,466201,46,124266,17,73482,96,541644,33,415.4,0,16,5488,4,+++++,+++,4292,0,3883,3,+++++,+++,2580,1

Your block output is 466MB/s, for something like 7 disks (14 disk 
RAID10).  So This means you are getting 66.6 MB/s per drive for write, 
and 77.4 MB/s per drive for read.

The 2TB RE4 drives can read at about 110 MB/s and write at about 105 
MB/s (from our tests in the lab).  So you are in the range of 60 to 70% 
efficiency.

Not bad.  RAID10 tends to be more efficient than RAID6 or RAID5 (at 
least the software versions of these).

-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics, Inc.
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