Re: Filesystem vs. Raw IO

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Tue, 1 Jun 2004 12:06:48 +0300
Message-ID: <0c8a01c447b7$c5c90790$8d879fd9@porgand>

> NetApp disk UFS filesystem: 48 sec
>
> NetApp disk raw space: 3 min 7 sec
>
>
>
> What should I be looking at? Why such a big difference?

What if you set your filesystemio_options to direct or setall in your UFS configuration? That way filesystem buffering for read-ahead purposes won't be used. Also set the db_file_multiblock_read_count to 1MB (128 for 8K blocks) in both configurations - that way raw IO has more chance to compete.

Tanel.

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Received on Tue Jun 01 2004 - 04:03:57 CDT