Re: RAID stripe size question

>> This is something I'd also would like to test, as a common
>> best-practice these days is to go for a SAME (stripe all, mirror
everything) setup.
>> From a development perspective it's easier to use SAME as the
>> developers won't have to think about physical location for new
>> tables/indices, so if there's no performance penalty with SAME I'll
>> gladly keep it that way.

>Usually, it's not the developers task to care about that, but the DBAs
responsibility.

As we don't have a full-time dedicated DBA (although I'm the one who do
most DBA related tasks) I would aim for making physical location as
transparent as possible, otherwise I'm afraid I won't be doing anything
else than supporting developers with that - and I *do* have other things
to do as well :)

>> In a previous test, using cd=5000 and cs=20 increased transaction
>> throughput by ~20% so I'll definitely fiddle with that in the coming
>> tests as well.

>How many parallel transactions do you have?

That was when running BenchmarkSQL
(http://sourceforge.net/projects/benchmarksql) with 100 concurrent users
("terminals"), which I assume means 100 parallel transactions at most.
The target application for this DB has 3-4 times as many concurrent
connections so it's possible that one would have to find other cs/cd
numbers better suited for that scenario. Tweaking bgwriter is another
task I'll look into as well..

Btw, here's the bonnie++ results from two different array sets (10+18,
4+24) on the MSA1500:

LUN: WAL, 10 disks, stripe size 32K
------------------------------------
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
sesell01 32G 56139 93 73250 22 16530 3 30488 45 57489 5
477.3 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
16 2458 90 +++++ +++ +++++ +++ 3121 99 +++++ +++
10469 98

LUN: WAL, 4 disks, stripe size 8K
----------------------------------
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
sesell01 32G 49170 82 60108 19 13325 2 15778 24 21489 2
266.4 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 2432 86 +++++ +++ +++++ +++ 3106 99 +++++ +++
10248 98

LUN: DATA, 18 disks, stripe size 32K
-------------------------------------
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
sesell01 32G 59990 97 87341 28 19158 4 30200 46 57556 6
495.4 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
16 1640 92 +++++ +++ +++++ +++ 1736 99 +++++ +++
10919 99

LUN: DATA, 24 disks, stripe size 64K
-------------------------------------
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
sesell01 32G 59443 97 118515 39 25023 5 30926 49 60835 6
531.8 1
------Sequential Create------ --------Random
Create--------
-Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
16 2499 90 +++++ +++ +++++ +++ 2817 99 +++++ +++
10971 100

Regards,
Mikael