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@xxxxxxxxxxxxxx > [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of Mage > Sent: Monday, January 17, 2005 9:01 PM > To: pgsql-general@xxxxxxxxxxxxxx > Subject: 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 > > > ---------------------------(end of > broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index > scan if your > joining column's datatypes do not match > > ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
