Re: Filesystem blocksize for archive logs on AIX

From: Nuno Souto <>
Date: Tue, 29 Oct 2013 20:18:21 +1100
Message-ID: <>

On 29/10/2013 3:00 AM, Rich Jesse wrote: > So, a 4K agblksize and 8K DB_BLOCK_SIZE?

I'm not sure what you mean by "a 4K agblocksize". JFS2 allows only a max 4K file system blocksize. That doesn't mean by any stretch the db cannot use larger block sizes. What does destroy the performance is to use a file system block size larger than the db block size.
No danger of that with JFS2 and db_block_size=8K! :)

But a clear danger of that, if using std redos (512) and a default file system blocksize of 4K,
as the other poster pointed out. That's when one has to match things. One way or the other.

>> We use a VMAX SAN with  4Gbps FC cards for P6 and 8Gbps FC cards for
 >> the P7.

> Interesting! I wonder how the VMAX compares with the XIV for performance.

Sorry, I don't have any comp figures. FWIW, we use also EMC's Powerpath. Which greatly enhances the performance for JFS2 and Aix.

> How many members in your redolog groups?

See the other reply.

Nuno Souto

Received on Tue Oct 29 2013 - 10:18:21 CET

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