Re: Write cache - Mailing list pgsql-hackers
| From | ohp@pyrenet.fr |
|---|---|
| Subject | Re: Write cache |
| Date | |
| Msg-id | Pine.UW2.4.53.0401272259340.24738@server.pyrenet.fr Whole thread Raw |
| In response to | Re: Write cache (Larry Rosenman <ler@lerctr.org>) |
| Responses |
Re: Write cache
|
| List | pgsql-hackers |
On Tue, 27 Jan 2004, Larry Rosenman wrote: > Date: Tue, 27 Jan 2004 15:55:49 -0600 > From: Larry Rosenman <ler@lerctr.org> > To: ohp@pyrenet.fr > Cc: pgsql-hackers list <pgsql-hackers@postgresql.org> > Subject: Re: Write cache > > > > --On Tuesday, January 27, 2004 22:48:42 +0100 ohp@pyrenet.fr wrote: > > > On Tue, 27 Jan 2004, Larry Rosenman wrote: > > > >> Date: Tue, 27 Jan 2004 15:45:20 -0600 > >> From: Larry Rosenman <ler@lerctr.org> > >> To: ohp@pyrenet.fr > >> Cc: pgsql-hackers list <pgsql-hackers@postgresql.org> > >> Subject: Re: Write cache > >> > >> > >> > >> --On Tuesday, January 27, 2004 22:43:34 +0100 ohp@pyrenet.fr wrote: > >> > >> > On Tue, 27 Jan 2004, Larry Rosenman wrote: > >> > > >> >> Date: Tue, 27 Jan 2004 15:38:30 -0600 > >> >> From: Larry Rosenman <ler@lerctr.org> > >> >> To: ohp@pyrenet.fr, pgsql-hackers list <pgsql-hackers@postgresql.org> > >> >> Subject: Re: Write cache > >> >> > >> >> IDE or SCSI? > >> > SCSI > >> >> > >> >> Why do you think the WC is screwing you? > >> >> > >> > Because after a sys crash, the most used filesystems (databases) are > >> > screwed > >> what VxFS mount options are you using? > > Nothing special... And any option I could use would'nt change a thing: the > > cache is on the disk itself... I did'nt look physicaly yet but according > > to the docs there's no way to disable it lik I always did on IBM... > > > > I was forced to buy those disk (more expensive, not better) > define not special? > > ISTM that the driver should force it out to the disk, unless the disk is > lying to the driver, or the driver is buggy. That's exactly what I think: the DISK has a write cache so it's lying to the controler saying data is written when it's only in the disk cache. That also would explain the fantastic write performance I have compared to read... > > > > > > >> > >> >> Which driver(s)? > >> >> > >> > Guess... ADPU320 > >> Hrm. > >> > >> >> LER > >> >> > >> >> > >> >> --On Tuesday, January 27, 2004 22:34:46 +0100 ohp@pyrenet.fr wrote: > >> >> > >> >> > Because I've lost a lot of data using postgresql (and I know for > >> >> > sure this should'nt happen) I've gone a bit further reading > >> >> > documentations on my disks and... > >> >> > > >> >> > I have FUJITSU MAP3367NC 36G 10000 rpm disks, those disk have a > >> >> > write cache of 8Mb, if someone could tell me hox to turn it off... > >> >> > Could'nt find it in the docs and this could very well explain why a > >> >> > busy database crashes every time > >> >> > > >> >> > Thanks for your help > >> >> > > >> >> > -- > >> >> > Olivier PRENANT Tel: +33-5-61-50-97-00 (Work) > >> >> > 6, Chemin d'Harraud Turrou +33-5-61-50-97-01 (Fax) > >> >> > 31190 AUTERIVE +33-6-07-63-80-64 (GSM) > >> >> > FRANCE Email: ohp@pyrenet.fr > >> >> > ------------------------------------------------------------------- > >> >> > --- --- ----- Make your life a dream, make your dream a reality. (St > >> >> > Exupery) > >> >> > >> >> > >> >> > >> >> > >> > > >> > -- > >> > Olivier PRENANT Tel: +33-5-61-50-97-00 (Work) > >> > 6, Chemin d'Harraud Turrou +33-5-61-50-97-01 (Fax) > >> > 31190 AUTERIVE +33-6-07-63-80-64 (GSM) > >> > FRANCE Email: ohp@pyrenet.fr > >> > ---------------------------------------------------------------------- > >> > --- ----- Make your life a dream, make your dream a reality. (St > >> > Exupery) > >> > >> > >> > >> > > > > -- > > Olivier PRENANT Tel: +33-5-61-50-97-00 (Work) > > 6, Chemin d'Harraud Turrou +33-5-61-50-97-01 (Fax) > > 31190 AUTERIVE +33-6-07-63-80-64 (GSM) > > FRANCE Email: ohp@pyrenet.fr > > ------------------------------------------------------------------------- > > ----- Make your life a dream, make your dream a reality. (St Exupery) > > > > -- Olivier PRENANT Tel: +33-5-61-50-97-00 (Work) 6, Chemin d'Harraud Turrou +33-5-61-50-97-01 (Fax) 31190 AUTERIVE +33-6-07-63-80-64 (GSM) FRANCE Email: ohp@pyrenet.fr ------------------------------------------------------------------------------ Make your life a dream, make your dream a reality. (St Exupery)
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