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Re: RE Tuning for performance
2006-08-24 12:00:33
On Thu, 24 Aug 2006 at 10:44am, Joshua Baker-LePain wrote
On Thu, 24 Aug 2006 at 4:36pm, Cyrille Bollu wrote
root@srv-fhq-bkp bonnie++-1.03a]# ./bonnie++ -u 0
(snip)
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
srv-fhq-bkp.fed 16G 36522 95 120980 60 58116 21 17956 49 56374 27
431.1 0
I see bad sequential input with getc but good (better than what I get with
Amanda) block sequential input.
The getc/putc perfomance is a measure of glibc, not your disks. The only
numbers I'm really interested in are the block output (i.e. reads) and block
input (i.e. writes) to the array. You can read from the array at
100MB/s, so that is *not* what is limiting your bandwidth to the tape
drive (unless the array is otherwise busy when you're trying to run backups).
Have you tried increasing amanda's blocksize and/or testing with 'tar -b'?
Well that's what I get for shooting my mouth off without checking myself.
Thanks to Jon LaBadie for pointing out that I got my meanings mixed above.
Output=>writes (good speed), input=>reads, and yours is not that hot and
can barely keep up with a LTO3 drive even when otherwise idle. So, play
with your RAID controller settings and see if you can't get better read
speeds. I'd throw in a tiobench test as well, to make sure you're not
optimizing against 1 benchmark.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
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