Message-ID: <464039AD.40407@inamo.no>
Date: Tue, 08 May 2007 10:49:49 +0200
From: =?ISO-8859-1?Q?Trygve_Laugst=F8l?= <trygvis@inamo.no>
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To: pgsql-performance@postgresql.org
Subject: Re: Best OS for Postgres 8.2
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david@lang.hm wrote:
> On Tue, 8 May 2007, Claus Guttesen wrote:
> 
>>> >  In #postgresql on freenode, somebody ever mentioned that ZFS from 
>>> >  Solaris
>>> >  helps a lot to the performance of pgsql, so dose anyone have 
>>> information
>>> >  about that?
>>>
>>>  the filesystem you use will affect the performance of postgres
>>>  significantly. I've heard a lot of claims for ZFS, unfortunantly 
>>> many of
>>>  them from people who have prooven that they didn't know what they were
>>>  talking about by the end of their first or second e-mails.
>>>
>>>  much of the hype for ZFS is it's volume management capabilities and 
>>> admin
>>>  tools. Linux has most (if not all) of the volume management 
>>> capabilities,
>>>  it just seperates them from the filesystems so that any filesystem 
>>> can use
>>>  them, and as a result you use one tool to setup your RAID, one to setup
>>>  snapshots, and a third to format your filesystems where ZFS does 
>>> this in
>>>  one userspace tool.
>>
>> Even though those posters may have proven them selves wrong, zfs is
>> still a very handy fs and it should not be judged relative to these
>> statements.
> 
> I don't disagree with you, I'm just noteing that too many of the 'ZFS is 
> great' posts need to be discounted as a result (the same thing goes for 
> the 'reiserfs4 is great' posts)
> 
>>>  once you seperate the volume management piece out, the actual 
>>> performance
>>>  question is a lot harder to answer. there are a lot of people who 
>>> say that
>>>  it's far faster then the alternate filesystems on Solaris, but I 
>>> haven't
>>>  seen any good comparisons between it and Linux filesystems.
>>
>> One could install pg on solaris 10 and format the data-area as ufs and
>> then as zfs and compare import- and query-times and other benchmarking
>> but comparing ufs/zfs to Linux-filesystems would also be a comparison
>> of those two os'es.
> 
> however, such a comparison is very legitimate, it doesn't really matter 
> which filesystem is better if the OS that it's tied to limits it so much 
> that the other one wins out with an inferior filesystem
> 
> currently ZFS is only available on Solaris, parts of it have been 
> released under GPLv2, but it doesn't look like enough of it to be ported 
> to Linux (enough was released for grub to be able to access it 
> read-only, but not the full filesystem). there are also patent concerns 
> that are preventing any porting to Linux.

This is not entirely correct. ZFS is only under the CDDL license and it 
has been ported to FreeBSD.

http://mail.opensolaris.org/pipermail/zfs-discuss/2007-April/026922.html

--
Trygve