Re: ext3

I recommend you don't use ext3 for any database:
http://seclists.org/lists/linux-kernel/2005/Jan/0641.html

apparently its still buggy.

Regards,
tzahi.

> -----Original Message-----
> From: pgsql-general-owner(at)postgresql(dot)org
> [mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of Mage
> Sent: Monday, January 17, 2005 9:01 PM
> To: pgsql-general(at)postgresql(dot)org
> Subject: [GENERAL] ext3
>
>
> Hello,
>
> Gabor Szima asked us to translate the letter below.
>
> "I read that ext3 writeback mode is recommended for
> PostgreSQL. I made
> some tests.
>
> data=ordered data=writeback
> ----------------------------------------------------------------------
> restoredb: 2m16.790s 1m42.367s
> UPDATE <tbl1> (17krows): 9.289s 7.147s
> UPDATE <tbl1> (17krows) (2.): 10.480s 3.778s
> VACUUM ANALYZE <tbl1>: 9.364s 0.986s !
> VACUUM FULL <tbl1>: 16.071s 2.575s
> REINDEX TABLE <tbl1>: 3.815s 1.886s
> ----------------------------------------------------------------------
>
> It's seductive.
> However I made some crash-tests too. Updated 4 tables
> simultaneously and
> recurring for 10 to 120s, then powered off the machine (without the
> reset button. i just pulled out the cable).
>
> SEQ RECOVERY-WARNINGS VACUUM
> -------------------------------
> 01: 1650 OK (WARNING: invalid page header in
> block 769 of relation "18800"; zeroing out page)
> 02: 3 FATAL (ERROR: could not access status of
> transaction 37814272)
> ------------------------------- (DETAIL: could not open file
> "/data/pgdata/pg_clog/0024": No such file or directory)
>
> I have stopped my tests at this point because this is not for
> production
> use. The database was corrupted.
>
>
> With ordered mode I got this:
>
> ext3-noatime,data=ordered:
>
> SEQ RECOVERY-WARNINGS VACUUM
> ------------------------------
> 01: 0 OK
> 02: 0 OK
> 03: 0 OK
> 04: 0 W,OK (relation "<tbl>" page 398 is
> uninitialized --- fixing)
> 05: 0 OK
> 06: 0 OK
> 07: 0 W,OK (relation "<tbl>" page 911 is
> uninitialized --- fixing)
> 08: 0 OK
> 09: 0 OK
> 10: 0 OK
> ------------------------------
>
> I think that writeback mode first records the data then the
> inode, and
> the ordered mode does it in reverse order. I also mean that postgres
> log requires the inode recorded correctly, the data loss is
> handled by
> the WAL.
>
> AMD XP2000, 512MB RAM, PostgreSQL 7.4.6 (i686), linux-2.4.28,
> gcc-3.3.5,
> Adaptec 29160, WD Enterprise 4360 (SCSI, SCA-80)
>
> I made mkfs and initdb before every tests and I repeated them
> in reverse
> order too. No quake3 ran in the background.
>
> -Sygma"
>
>
> Sorry for my english.
>
>
> Mage
>
>
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