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Re: What`s wrong with JFS configuration?

From: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
To: Paweł Gruszczyński <pawel(dot)gruszczynski(at)inea(dot)com(dot)pl>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: What`s wrong with JFS configuration?
Date: 2007-04-25 08:54:12
Message-ID: 462F1734.3080705@enterprisedb.com (view raw or flat)
Thread:
Lists: pgsql-performance
Paweł Gruszczyński wrote:
> To test I use pgBench with default database schema, run for 25, 50, 75 
> users at one time. Every test I run 5 time to take average.
> Unfortunetly my result shows that ext is fastest, ext3 and jfs are very 
> simillar. I can understand that ext2 without jurnaling is faster than 
> ext3, it is said that jfs is 40 - 60% faster. I cant see the difference. 
> Part of My results: (transaction type | scaling factor | num of clients 
> | tpl | num on transactions | tps including connection time | tps 
> excliding connection time)
> 
> EXT2:
> 
> TPC-B (sort of),50,75,13,975|975,338.286682,358.855582
> ...
> 
> Can anyone tell me what`s wrong with my test? Or maybe it is normal?

With a scaling factor of 50, your database size is ~ 1 GB, which fits 
comfortably in your RAM. You're not exercising your drives or filesystem 
much. Assuming you haven't disabled fsync, the performance of that test 
is bound by the speed your drives can flush WAL commit records to disk.

I wouldn't expect the filesystem to make a big difference anyway, but 
you'll see..

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com

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Subject: Re: What`s wrong with JFS configuration?
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