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  1. Postgresql on file system EXT2 or EXT3

    Carmen Wai <wai_carmen@hotmail.com> — 2003-11-27T15:00:30Z

    Hello:

I would like to know whether there is any different in installing Postgresql 
on the Linux system with file system of EXT2 or EXT3. I have two machines 
with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with 
different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000 
records to the two machines, I found that the machine with EXT2 insert much 
quicker than the other with EXT3.

Is postgresqk perform better with EXT2 file system?

Thanks a lot!
Carmen

_________________________________________________________________
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  2. Re: Postgresql on file system EXT2 or EXT3

    Andrew Sullivan <andrew@libertyrms.info> — 2003-11-27T15:40:56Z

    On Thu, Nov 27, 2003 at 03:00:30PM +0000, Carmen Wai wrote:
> 
> Is postgresqk perform better with EXT2 file system?

Anything that writes on the filesystem is faster with ext2.  It's
also less reliable.

A

-- 
----
Andrew Sullivan                         204-4141 Yonge Street
Afilias Canada                        Toronto, Ontario Canada
<andrew@libertyrms.info>                              M2P 2A8
                                         +1 416 646 3304 x110

  3. Re: Postgresql on file system EXT2 or EXT3

    Rich Shepard <rshepard@appl-ecosys.com> — 2003-11-27T17:10:22Z

    On Thu, 27 Nov 2003, Carmen Wai wrote:

> I would like to know whether there is any different in installing Postgresql
> on the Linux system with file system of EXT2 or EXT3. I have two machines
> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
> different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000
> records to the two machines, I found that the machine with EXT2 insert much
> quicker than the other with EXT3.
>
> Is postgresqk perform better with EXT2 file system?

Carmen,

  Consider the overhead in having the security of a journaling file system
when you make your comparisons.

Rich

-- 
Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc. (TM)
<http://www.appl-ecosys.com>

  4. Re: Postgresql on file system EXT2 or EXT3

    Keith C. Perry <netadmin@vcsn.com> — 2003-11-27T18:03:41Z

    Quoting Carmen Wai <wai_carmen@hotmail.com>:

> Hello:
> 
> I would like to know whether there is any different in installing Postgresql
> 
> on the Linux system with file system of EXT2 or EXT3. I have two machines 
> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with 
> different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000
> 
> records to the two machines, I found that the machine with EXT2 insert much 
> quicker than the other with EXT3.
> 
> Is postgresqk perform better with EXT2 file system?
> 
> Thanks a lot!
> Carmen
> 
> _________________________________________________________________
> Linguaphone :  Learning English? Get Japanese lessons for FREE 
> http://go.msnserver.com/HK/30476.asp
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
> 

Keep in mind that with a journaling type fs, you have additional overhead for
the journal.  I've heard people make this comment before about EXT 3 being
slower that EXT 2.  I personally haven't seen any signficant slow down but for
Linux keep in mind that you could also use ReiserFS which I've heard is faster
than EXT 3 in the same scenario.  JFS is also an option.

You might also want to adjust your inode size down on the EXT2/3 filesystems. 
The default is 4k.  I use 2k but you can go as low as 1k.  Thats not something
you can do on the fly though.  You'll have to backup everything and redo the
filesystem.

-- 
Keith C. Perry, MS E.E.
Director of Networks & Applications
VCSN, Inc.
http://vcsn.com
 
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  5. Re: Postgresql on file system EXT2 or EXT3

    Richard Welty <rwelty@averillpark.net> — 2003-11-27T18:15:13Z

    On Thu, 27 Nov 2003 13:03:41 -0500 "Keith C. Perry" <netadmin@vcsn.com> wrote:
> Quoting Carmen Wai <wai_carmen@hotmail.com>:
> > records to the two machines, I found that the machine with EXT2 insert much 
> > quicker than the other with EXT3.
 
> > Is postgresqk perform better with EXT2 file system?
 
> Keep in mind that with a journaling type fs, you have additional overhead for
> the journal.  I've heard people make this comment before about EXT 3 being
> slower that EXT 2. 

based on what i've heard hanging out on various postgresql lists, try EXT3
with journaling of meta data only for the database files.

richard
-- 
Richard Welty                                         rwelty@averillpark.net
Averill Park Networking                                         518-573-7592
    Java, PHP, PostgreSQL, Unix, Linux, IP Network Engineering, Security

  6. Re: Postgresql on file system EXT2 or EXT3

    Mike Benoit <mikeb@netnation.com> — 2003-11-27T20:18:02Z

    It's simply a matter of file system performance, take a look at the
below URL to get a better idea:

http://fsbench.netnation.com/

EXT2 is fast, but like other people mentioned, FSCK'ing a large
partition could mean hours of downtime. There are other file systems
that offer journaling as well as decent performance. As far as EXT3 is
concerned, its near the bottom of the performance list. 

On Thu, 2003-11-27 at 07:00, Carmen Wai wrote:
> Hello:
> 
> I would like to know whether there is any different in installing Postgresql 
> on the Linux system with file system of EXT2 or EXT3. I have two machines 
> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with 
> different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000 
> records to the two machines, I found that the machine with EXT2 insert much 
> quicker than the other with EXT3.
> 
> Is postgresqk perform better with EXT2 file system?
> 
> Thanks a lot!
> Carmen
> 
> _________________________________________________________________
> Linguaphone :  Learning English? Get Japanese lessons for FREE 
> http://go.msnserver.com/HK/30476.asp
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
-- 
Best Regards,
 
Mike Benoit

  7. Re: Postgresql on file system EXT2 or EXT3

    Craig O'Shannessy <craig@ucw.com.au> — 2003-11-28T01:04:26Z

    One important point here is reboot time after a crash or non-clean 
shutdown.

A very large ext2 file system can take a LONG time to do an integrity 
check on reboot (30 minutes?), and may lose data.

The same partition with ext3 enabled will run it's journalled recovery in 
a couple of seconds, marking crash recovery MUCH faster and safer.

I don't think this should be ignored in a discussion of these filesystems.  
Reboot time can be a real killer with ext2, even without the potential for 
data loss.

Craig

On Thu, 27 Nov 2003, Rich Shepard wrote:

> On Thu, 27 Nov 2003, Carmen Wai wrote:
> 
> > I would like to know whether there is any different in installing Postgresql
> > on the Linux system with file system of EXT2 or EXT3. I have two machines
> > with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
> > different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000
> > records to the two machines, I found that the machine with EXT2 insert much
> > quicker than the other with EXT3.
> >
> > Is postgresqk perform better with EXT2 file system?
> 
> Carmen,
> 
>   Consider the overhead in having the security of a journaling file system
> when you make your comparisons.
> 
> Rich
> 
>

  8. Re: Postgresql on file system EXT2 or EXT3

    Terry Fielder <terry@ashtonwoodshomes.com> — 2003-11-28T01:16:22Z

    Been there, done that.

I'll buy more memory to help overcome the (I find subtle) disk performance
issue long before I will give up a journalling file system:  Telling the
users they have to wait 20 min for the system to come back is a bitter pill
to swallow.  With a journalling file system most linux systems are back up
within 120 seconds, and many types of users may not even notice it was down.
:)

Terry Fielder
Manager Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
terry@greatgulfhomes.com
Fax: (416) 441-9085


> -----Original Message-----
> From: pgsql-general-owner@postgresql.org
> [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Craig
> O'Shannessy
> Sent: Thursday, November 27, 2003 8:04 PM
> To: Rich Shepard
> Cc: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] Postgresql on file system EXT2 or EXT3
>
>
> One important point here is reboot time after a crash or non-clean
> shutdown.
>
> A very large ext2 file system can take a LONG time to do an integrity
> check on reboot (30 minutes?), and may lose data.
>
> The same partition with ext3 enabled will run it's journalled
> recovery in
> a couple of seconds, marking crash recovery MUCH faster and safer.
>
> I don't think this should be ignored in a discussion of these
> filesystems.
> Reboot time can be a real killer with ext2, even without the
> potential for
> data loss.
>
> Craig
>
> On Thu, 27 Nov 2003, Rich Shepard wrote:
>
> > On Thu, 27 Nov 2003, Carmen Wai wrote:
> >
> > > I would like to know whether there is any different in
> installing Postgresql
> > > on the Linux system with file system of EXT2 or EXT3. I
> have two machines
> > > with idential OS (Red Hat 7.3 install with postgresql
> 7.3.4) but with
> > > different file system, 1 is EXT2 and the other is EXT3.
> When I insert 10,000
> > > records to the two machines, I found that the machine
> with EXT2 insert much
> > > quicker than the other with EXT3.
> > >
> > > Is postgresqk perform better with EXT2 file system?
> >
> > Carmen,
> >
> >   Consider the overhead in having the security of a
> journaling file system
> > when you make your comparisons.
> >
> > Rich
> >
> >
>
>
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>

  9. Re: Postgresql on file system EXT2 or EXT3

    Chris Browne <cbbrowne@acm.org> — 2003-11-28T02:06:25Z

    Centuries ago, Nostradamus foresaw when rshepard@appl-ecosys.com (Rich Shepard) would write:
> On Thu, 27 Nov 2003, Carmen Wai wrote:
>
>> I would like to know whether there is any different in installing Postgresql
>> on the Linux system with file system of EXT2 or EXT3. I have two machines
>> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
>> different file system, 1 is EXT2 and the other is EXT3. When I insert 10,000
>> records to the two machines, I found that the machine with EXT2 insert much
>> quicker than the other with EXT3.
>>
>> Is postgresqk perform better with EXT2 file system?
>
> Carmen,
>
>   Consider the overhead in having the security of a journaling file system
> when you make your comparisons.

Consider also the overhead of a four hour e2fsck when you make the
comparisons.  

And that's four hours that may still leave you with a seriously
hurting database, perhaps still irretrievable.

If the cost is so vastly too much, then the Right Answer is to spend
an extra $1.5K on a MegaRAID controller that will make the cost of the
journal fairly much disappear.

Ah yes, reminder to self...  Need to kick off a data copy that, if my
theory is right, will knock a beefy JFS-based Linux box to the ground,
giving it a good "upper cut" that will hopefully help diagnose some
serious problems we have been seeing in this regard...

So far, this particular server has not been giving great confidence in
the stability of Linux for _big_ DBMS servers... :-(
-- 
let name="cbbrowne" and tld="cbbrowne.com" in String.concat "@" [name;tld];;
http://www.ntlug.org/~cbbrowne/languages.html
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  10. Re: Postgresql on file system EXT2 or EXT3

    Ben-Nes Michael <miki@canaan.co.il> — 2003-11-28T07:34:35Z

    Don't go on EXT2, its not reliable and takes lots of time to start after an
unclean shutdown. ( all the other explained it quite well )

The most promising FS is Reiserfs v4
http://www.namesys.com/v4/v4.html

If you cant wait I suggest XFS or JFS.

Look in the archives for all the explanations.

Ohhh, and don't use IDE Drives, only SCSI.

Cheer
--------------------------
Canaan Surfing Ltd.
Internet Service Providers
Ben-Nes Michael - Manager
Tel: 972-4-6991122
Fax: 972-4-6990098
http://www.canaan.net.il
--------------------------
----- Original Message ----- 
From: "Carmen Wai" <wai_carmen@hotmail.com>
To: <pgsql-general@postgresql.org>
Sent: Thursday, November 27, 2003 5:00 PM
Subject: [GENERAL] Postgresql on file system EXT2 or EXT3


> Hello:
>
> I would like to know whether there is any different in installing
Postgresql
> on the Linux system with file system of EXT2 or EXT3. I have two machines
> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
> different file system, 1 is EXT2 and the other is EXT3. When I insert
10,000
> records to the two machines, I found that the machine with EXT2 insert
much
> quicker than the other with EXT3.
>
> Is postgresqk perform better with EXT2 file system?
>
> Thanks a lot!
> Carmen
>
> _________________________________________________________________
> Linguaphone :  Learning English? Get Japanese lessons for FREE
> http://go.msnserver.com/HK/30476.asp
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
>

  11. Re: Postgresql on file system EXT2 or EXT3

    Joshua D. Drake <jd@commandprompt.com> — 2003-11-28T17:22:39Z

    | Don't go on EXT2, its not reliable and takes lots of time to start 
after an

Actually EXT2 is quite reliable and it is also quite fast. However your
point is accurate about start up time after a crash.

>The most promising FS is Reiserfs v4
>http://www.namesys.com/v4/v4.html
>
>  
>
Although Reiser is promising, I wouldn't touch it. It is beta, frankly my
experience is that even their stable stuff is still beta.

If you want a native, reliable, stable FS for Linux. Use JFS or XFS 
(when 2.6 comes out)

Sincerely,

Joshua D. Drake








>If you cant wait I suggest XFS or JFS.
>
>Look in the archives for all the explanations.
>
>Ohhh, and don't use IDE Drives, only SCSI.
>
>Cheer
>--------------------------
>Canaan Surfing Ltd.
>Internet Service Providers
>Ben-Nes Michael - Manager
>Tel: 972-4-6991122
>Fax: 972-4-6990098
>http://www.canaan.net.il
>--------------------------
>----- Original Message ----- 
>From: "Carmen Wai" <wai_carmen@hotmail.com>
>To: <pgsql-general@postgresql.org>
>Sent: Thursday, November 27, 2003 5:00 PM
>Subject: [GENERAL] Postgresql on file system EXT2 or EXT3
>
>
>  
>
>>Hello:
>>
>>I would like to know whether there is any different in installing
>>    
>>
>Postgresql
>  
>
>>on the Linux system with file system of EXT2 or EXT3. I have two machines
>>with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
>>different file system, 1 is EXT2 and the other is EXT3. When I insert
>>    
>>
>10,000
>  
>
>>records to the two machines, I found that the machine with EXT2 insert
>>    
>>
>much
>  
>
>>quicker than the other with EXT3.
>>
>>Is postgresqk perform better with EXT2 file system?
>>
>>Thanks a lot!
>>Carmen
>>
>>_________________________________________________________________
>>Linguaphone :  Learning English? Get Japanese lessons for FREE
>>http://go.msnserver.com/HK/30476.asp
>>
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 7: don't forget to increase your free space map settings
>>
>>    
>>
>
>
>
>---------------------------(end of broadcast)---------------------------
>TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
>  
>

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  12. Re: Postgresql on file system EXT2 or EXT3

    Christopher Browne <cbbrowne@libertyrms.info> — 2003-11-28T18:40:14Z

    miki@canaan.co.il ("Ben-Nes Michael") writes:
> Don't go on EXT2, its not reliable and takes lots of time to start after an
> unclean shutdown. ( all the other explained it quite well )
>
> The most promising FS is Reiserfs v4
> http://www.namesys.com/v4/v4.html
>
> If you cant wait I suggest XFS or JFS.

ReiserFS may seem "promising," but I wouldn't touch it for DBMS work
for quite some time to come.

Its design has always been directed to the efficient handling of tiny
files, and I don't see version 4 changing that.  That's not ideal for
PostgreSQL, because it tends to access fairly large files.

ReiserFS has a history of losing data when crashes take place (e.g. -
unclean shutdown).  I haven't experienced any _enormous_ horrors, but
have experienced enough small problems that I'm not interested in
having DBMS files on it...
-- 
let name="cbbrowne" and tld="libertyrms.info" in String.concat "@" [name;tld];;
<http://dev6.int.libertyrms.com/>
Christopher Browne
(416) 646 3304 x124 (land)

  13. Re: Postgresql on file system EXT2 or EXT3

    Bruce Momjian <pgman@candle.pha.pa.us> — 2003-11-28T21:40:18Z

    Ben-Nes Michael wrote:
> Don't go on EXT2, its not reliable and takes lots of time to start after an
> unclean shutdown. ( all the other explained it quite well )
> 
> The most promising FS is Reiserfs v4
> http://www.namesys.com/v4/v4.html
> 
> If you cant wait I suggest XFS or JFS.

We have gotten documented reports that JFS is fastest, followed closely
by XFS, and Reiser (fast but consumes more CPU), and finally ext3.

While several folks have trumpeted the fast fsck for these journalling
file systems, their _big_ advantage is robust recovery after a crash,
which ext2 can not guarantee.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

  14. Re: Postgresql on file system EXT2 or EXT3

    Mike Benoit <mikeb@netnation.com> — 2003-11-28T22:46:50Z

    On Fri, 2003-11-28 at 10:40, Christopher Browne wrote:
> miki@canaan.co.il ("Ben-Nes Michael") writes:
> > Don't go on EXT2, its not reliable and takes lots of time to start after an
> > unclean shutdown. ( all the other explained it quite well )
> >
> > The most promising FS is Reiserfs v4
> > http://www.namesys.com/v4/v4.html
> >
> > If you cant wait I suggest XFS or JFS.
> 
> ReiserFS may seem "promising," but I wouldn't touch it for DBMS work
> for quite some time to come.
> 
> Its design has always been directed to the efficient handling of tiny
> files, and I don't see version 4 changing that.  That's not ideal for
> PostgreSQL, because it tends to access fairly large files.

I wouldn't be so quick to judge. While you are correct that ReiserFS v3
had small files in mind during its design process, v4 is attempting to
be the best of both worlds. This is evident by its "extents" mode, which
if I recall correctly is one method that XFS uses to get decent
performance with large files. (Take a look at:
http://kerneltrap.org/node/view/741) 

> 
> ReiserFS has a history of losing data when crashes take place (e.g. -
> unclean shutdown).  I haven't experienced any _enormous_ horrors, but
> have experienced enough small problems that I'm not interested in
> having DBMS files on it...

ReiserFS v3 by default only journals meta-data, so this may be what your
referring to, which is the same problem you would get with EXT3 in
write-back mode. 

However Reiser4 is a completely different beast, in that its fully
atomic, so AFAIK it has no concept of meta-data journaling, data
journaling, or any of that. Writes either complete successfully or they
don't, so in theory Reiser4 should be the "safest" file system available
for Linux in this regard. According to http://fsbench.netnation.com,
Reiser4 is already showing _very_ impressive performance. Though it uses
more CPU than most of the other file systems, its so much faster that it
almost evens out. Having said all this, Reiser4 is no where near
production ready, but it will be something to keep an eye on. 

If your database is I/O bound, XFS would be a good choice, if its CPU
bound, JFS (JFS tends to use the least amount of CPU, at the expense of
some speed). 

I would be very interested in seeing actual PGBENCH results with
databases on the different file systems, thats the only way you will
know for sure which file system is best for the task.

-- 
Best Regards,
 
Mike Benoit
NetNation Communications Inc.
Systems Engineer
Tel: 604-684-6892 or 888-983-6600
 ---------------------------------------
 
 Disclaimer: Opinions expressed here are my own and not 
 necessarily those of my employer

  15. Re: Postgresql on file system EXT2 or EXT3

    Tony <tony@unihost.net> — 2003-11-29T10:07:17Z

    I'm in agreement with Joshua in some aspects of his reply but not 
others.  I use Reiserfs on many production servers and have done so for 
a couple of years.  I have needed perform one repair only on the 
filesystem, which was automated with the tools provided.  Reiser is 
still beta, in the same way that Debian uses the term testing to refer 
to non-"stable" software.  Many people us it in a production environment 
successfully.  But, as a caveat to my praises to Reiser, if you decide 
to use it , understand that you *must* know your subject, how to use the 
tools and how to recover from failures.  It is not enough to merely rely 
on fsck getting the job done, and, in some circumstances the 
incantations required to performa fix can be quite terse IMHO.

The next fs I install will be XFS after much deliberation and 
conversation with like minded fellow compugeeks, since it's at least as 
good as any other journaling fs, but has the added bonus that 
filesystems can be *grown* without the aid of LVM, etc.  Which would be 
a huge bonus.

Just my 2 cents.

Tony.

Joshua D. Drake wrote:

> | Don't go on EXT2, its not reliable and takes lots of time to start 
> after an
>
> Actually EXT2 is quite reliable and it is also quite fast. However your
> point is accurate about start up time after a crash.
>
>> The most promising FS is Reiserfs v4
>> http://www.namesys.com/v4/v4.html
>>
>>  
>>
> Although Reiser is promising, I wouldn't touch it. It is beta, frankly my
> experience is that even their stable stuff is still beta.
>
> If you want a native, reliable, stable FS for Linux. Use JFS or XFS 
> (when 2.6 comes out)
>
> Sincerely,
>
> Joshua D. Drake
>
>
>
>
>
>
>
>
>> If you cant wait I suggest XFS or JFS.
>>
>> Look in the archives for all the explanations.
>>
>> Ohhh, and don't use IDE Drives, only SCSI.
>>
>> Cheer
>> --------------------------
>> Canaan Surfing Ltd.
>> Internet Service Providers
>> Ben-Nes Michael - Manager
>> Tel: 972-4-6991122
>> Fax: 972-4-6990098
>> http://www.canaan.net.il
>> --------------------------
>> ----- Original Message ----- From: "Carmen Wai" <wai_carmen@hotmail.com>
>> To: <pgsql-general@postgresql.org>
>> Sent: Thursday, November 27, 2003 5:00 PM
>> Subject: [GENERAL] Postgresql on file system EXT2 or EXT3
>>
>>
>>  
>>
>>> Hello:
>>>
>>> I would like to know whether there is any different in installing
>>>   
>>
>> Postgresql
>>  
>>
>>> on the Linux system with file system of EXT2 or EXT3. I have two 
>>> machines
>>> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
>>> different file system, 1 is EXT2 and the other is EXT3. When I insert
>>>   
>>
>> 10,000
>>  
>>
>>> records to the two machines, I found that the machine with EXT2 insert
>>>   
>>
>> much
>>  
>>
>>> quicker than the other with EXT3.
>>>
>>> Is postgresqk perform better with EXT2 file system?
>>>
>>> Thanks a lot!
>>> Carmen
>>>
>>> _________________________________________________________________
>>> Linguaphone :  Learning English? Get Japanese lessons for FREE
>>> http://go.msnserver.com/HK/30476.asp
>>>
>>>
>>> ---------------------------(end of 
>>> broadcast)---------------------------
>>> TIP 7: don't forget to increase your free space map settings
>>>
>>>   
>>
>>
>>
>>
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>>  
>>
>

  16. Re: Postgresql on file system EXT2 or EXT3

    Andrew Sullivan <andrew@libertyrms.info> — 2003-11-29T14:06:58Z

    On Fri, Nov 28, 2003 at 02:46:50PM -0800, Mike Benoit wrote:
> I would be very interested in seeing actual PGBENCH results with
> databases on the different file systems, thats the only way you will
> know for sure which file system is best for the task.

I suspect because of the nature of its workload, in my experience
pg_bench is lousy for measuring filesystem performance: it always
bottlenecks somewhere else.

Chris Browne did some work for us some time ago evaluating XFS, JFS,
and ext3, and concluded that JFS was the best under a high-update
load; that workload was selected precisely because it was I/O bound. 
I thought he sent the results to the -performance list, but I can't
put my hands on the email right now.  Chris?

A

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Andrew Sullivan                         204-4141 Yonge Street
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<andrew@libertyrms.info>                              M2P 2A8
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  17. Re: Postgresql on file system EXT2 or EXT3

    Chris Browne <cbbrowne@acm.org> — 2003-11-29T16:35:30Z

    Centuries ago, Nostradamus foresaw when andrew@libertyrms.info (Andrew Sullivan) would write:
> On Fri, Nov 28, 2003 at 02:46:50PM -0800, Mike Benoit wrote:
>> I would be very interested in seeing actual PGBENCH results with
>> databases on the different file systems, thats the only way you
>> will know for sure which file system is best for the task.
>
> I suspect because of the nature of its workload, in my experience
> pg_bench is lousy for measuring filesystem performance: it always
> bottlenecks somewhere else.
>
> Chris Browne did some work for us some time ago evaluating XFS, JFS,
> and ext3, and concluded that JFS was the best under a high-update
> load; that workload was selected precisely because it was I/O
> bound. I thought he sent the results to the -performance list, but I
> can't put my hands on the email right now.  Chris?

Yes, that's right, and the paucity of hard-and-fast details comes from
the fact that the sample workload was, well, pretty proprietary.  It
was an honest-to-goodness real workload for one of the registries,
which means that I can't give out copies.  (With suitable caveats of
"or else I'd have to kill you," or, more realistically "or else they'd
have to kill me..."  :-(.)

The results repeated well, with JFS being ~20% faster than ext3 or
XFS.  (I found XFS marginally slower for this benchmark than ext3, but
the difference was small enough that I wouldn't trust that as a True
Conclusion.)

The actual measurements are probably in the internal Systems archives;
I am generally disinclined to give out numbers publicly, in view of
the public unavailability of the workload.

What I had previously reported was actually on the pgsql-admin list... 
<http://archives.postgresql.org/pgsql-admin/2003-09/msg00284.php>
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  18. Re: Postgresql on file system EXT2 or EXT3

    Mike Benoit <mikeb@netnation.com> — 2003-12-02T19:18:02Z

    On Sat, 2003-11-29 at 02:07, Unihost Web Hosting wrote:
> The next fs I install will be XFS after much deliberation and 
> conversation with like minded fellow compugeeks, since it's at least as 
> good as any other journaling fs, but has the added bonus that 
> filesystems can be *grown* without the aid of LVM, etc.  Which would be 
> a huge bonus.
> 

resize_reiserfs
resize2fs

We grow a EXT3 file system all the time on a Linear RAID array. Works
fine without LVM. Shrinking can be a different issue though.

> Just my 2 cents.
> 
> Tony.
> 
> Joshua D. Drake wrote:
> 
> > | Don't go on EXT2, its not reliable and takes lots of time to start 
> > after an
> >
> > Actually EXT2 is quite reliable and it is also quite fast. However your
> > point is accurate about start up time after a crash.
> >
> >> The most promising FS is Reiserfs v4
> >> http://www.namesys.com/v4/v4.html
> >>
> >>  
> >>
> > Although Reiser is promising, I wouldn't touch it. It is beta, frankly my
> > experience is that even their stable stuff is still beta.
> >
> > If you want a native, reliable, stable FS for Linux. Use JFS or XFS 
> > (when 2.6 comes out)
> >
> > Sincerely,
> >
> > Joshua D. Drake
> >
> >
> >
> >
> >
> >
> >
> >
> >> If you cant wait I suggest XFS or JFS.
> >>
> >> Look in the archives for all the explanations.
> >>
> >> Ohhh, and don't use IDE Drives, only SCSI.
> >>
> >> Cheer
> >> --------------------------
> >> Canaan Surfing Ltd.
> >> Internet Service Providers
> >> Ben-Nes Michael - Manager
> >> Tel: 972-4-6991122
> >> Fax: 972-4-6990098
> >> http://www.canaan.net.il
> >> --------------------------
> >> ----- Original Message ----- From: "Carmen Wai" <wai_carmen@hotmail.com>
> >> To: <pgsql-general@postgresql.org>
> >> Sent: Thursday, November 27, 2003 5:00 PM
> >> Subject: [GENERAL] Postgresql on file system EXT2 or EXT3
> >>
> >>
> >>  
> >>
> >>> Hello:
> >>>
> >>> I would like to know whether there is any different in installing
> >>>   
> >>
> >> Postgresql
> >>  
> >>
> >>> on the Linux system with file system of EXT2 or EXT3. I have two 
> >>> machines
> >>> with idential OS (Red Hat 7.3 install with postgresql 7.3.4) but with
> >>> different file system, 1 is EXT2 and the other is EXT3. When I insert
> >>>   
> >>
> >> 10,000
> >>  
> >>
> >>> records to the two machines, I found that the machine with EXT2 insert
> >>>   
> >>
> >> much
> >>  
> >>
> >>> quicker than the other with EXT3.
> >>>
> >>> Is postgresqk perform better with EXT2 file system?
> >>>
> >>> Thanks a lot!
> >>> Carmen
> >>>
> >>> _________________________________________________________________
> >>> Linguaphone :  Learning English? Get Japanese lessons for FREE
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Systems Engineer
Tel: 604-684-6892 or 888-983-6600
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 Disclaimer: Opinions expressed here are my own and not 
 necessarily those of my employer