RE: Filesystem for Linux production database server?

Reiserfs' biggest strength is in its ability to deal with directories with huge numbers of files in a very speedy fashion. Obviously, for oracle this is less relevant.

As far as the max-readahead option, I don't understand the specific relevance to fibre-attached storage. I would imagine, though admittedly I no longer have large storage arrays to play with, that setting readahead to be higher could damage performance against arrays with "intelligent" caching algorithms. Having the OS handle read-ahead rather than the array will likely fool the array into thinking that the i/o patterns are more sequential than they are. This will cause them to pre-allocate cache regions and pre-fetch more tracks off disk, which could adversely impact performance.

Totally separate from that, Redhat strongly advises _against_ tuning that parameter.

I happen to be doing I/O testing right now anyway, so maybe I'll gen up some workloads on different filesystems and go nuts.

Thanks,
Matt

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Matthew Zito
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> -----Original Message-----

> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On 

> Behalf Of Craig I. Hagan

> Sent: Wednesday, July 02, 2003 4:11 AM

> To: Multiple recipients of list ORACLE-L

> Subject: Re: Filesystem for Linux production database server?

> 

> 

> > Linux file systems usually do not support direct I/O (bypassing the 

> > buffer cache), which means that you're going to have double caching 

> > with almost

> 

> This is no longer the case. Look at the O_DIRECT open option, 

> which can be used with oracle. Make sure that your 

> distribution has support for it.

> 

<snip> 


> One other thing: if you are using fibre attached storage and 

> are *not* using async io, then put some usefully large value 

> into /proc/sys/vm/max-readahead, remember it is power of 2 

> minus one, so youd want to look at values like 255, 511, and 1023.

> 

> 

> > As for availability, you'll have to go with some RAID 

> controller and 

> > standby

> > database or RAC. In case of RAC, your choice of file 

> systems is clear (OCFS).

> > Whatever you do, do not configure your RAID as RAID-5 but 

> RAID 1+0 (BARF).

> 

> what he said, save that i like raid10.

> 

>  

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