On Tue, Sep 13, 2011 at 12:13 PM, Samuel Gendler <sgend...@ideasculptor.com>wrote:
> I'm just beginning the process of benchmarking and tuning a new server. > Something I really haven't done before. I'm using Greg's book as a guide. > I started with bonnie++ (1.96) and immediately got anomalous results (I > think). > > Hardware is as follows: > > 2x quad core xeon 5504 2.0Ghz, 2x4MB cache > 192GB DDR3 1066 RAM > 24x600GB 15K rpm SAS drives > adaptec 52445 controller > > The default config, being tested at the moment, has 2 volumes, one 100GB > and one 3.2TB, both are built from a stripe across all 24 disks, rather than > splitting some spindles out for one volume and another set for the other > volume. At the moment, I'm only testing against the single 3.2TB volume. > > The smaller volume is partitioned into /boot (ext2 and tiny) and / (ext4 > and 91GB). The larger volume is mounted as xfs with the following options > (cribbed from an email to the list earlier this week, I > think): logbufs=8,noatime,nodiratime,nobarrier,inode64,allocsize=16m > > Bonnie++ delivered the expected huge throughput for sequential read and > write. It seems in line with other benchmarks I found online. However, we > are only seeing 180 seeks/sec, but seems quite low. I'm hoping someone > might be able to confirm that and. hopefully, make some suggestions for > tracking down the problem if there is one. > > Results are as follows: > > > 1.96,1.96,newbox,1,1315935572,379G,,1561,99,552277,46,363872,34,3005,90,981924,49,179.1,56,16,,,,,19107,69,+++++,+++,20006,69,19571,72,+++++,+++,20336,63,7111us,10666ms,14067ms,65528us,592ms,170ms,949us,107us,160us,383us,31us,130us > > > Version 1.96 ------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 > newzonedb.z1.p 379G 1561 99 552277 46 363872 34 3005 90 981924 49 > 179.1 56 > Latency 7111us 10666ms 14067ms 65528us 592ms > 170ms > ------Sequential Create------ --------Random > Create-------- > -Create-- --Read--- -Delete-- -Create-- --Read--- > -Delete-- > files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec > %CP > newbox 16 19107 69 +++++ +++ 20006 69 19571 72 +++++ +++ > 20336 63 > Latency 949us 107us 160us 383us 31us > 130us > > My seek times increase when I reduce the size of the file, which isn't surprising, since once everything fits into cache, seeks aren't dependent on mechanical movement. However, I am seeing lots of bonnie++ results in google which appear to be for a file size that is 2x RAM which show numbers closer to 1000 seeks/sec (compared to my 180). Usually, I am seeing 16GB file for 8GB hosts. So what is an acceptable random seeks/sec number for a file that is 2x memory? And does file size make a difference independent of available RAM such that the enormous 379GB file that is created on my host is skewing the results to the low end?
