Re: [PERFORM] fsync and battery-backed caches

2006-02-28 Thread Javier Somoza
Yeah, i saw it. It says full-page-writes can be disabled without problems. But i wanted to confirm fsync cannot be disabled although i have battery. Thanks!! :-) We do mention battery-backed cache in our docs: http://www.postgresql.org/docs/8.1/static/wal.html If it is unclear,

Re: [PERFORM] fsync and battery-backed caches

2006-02-28 Thread Javier Somoza
Ups sorry. Actually, you can't assume that a BBU means you can safely disable full-page-writes. Depending on the controller, it's still possible to end up with partially written pages. BTW, if your mailer makes doing so convenient, it would be nice to trim down your .signature; note that

Re: [PERFORM] fsync and battery-backed caches

2006-02-28 Thread Jim C. Nasby
Ok, you absolutely can't guarantee you won't get partial page writes then. A UPS buys you no more data safety than being plugged directly into the wall. UPS's fail. People trip over cords. Breakers fail. Even if you have multiple power supplies on multiple circuits fed by different UPS's you can

[PERFORM] fsync and battery-backed caches

2006-02-27 Thread Javier Somoza
Hi all Is it secure to disable fsync havin battery-backed disk cache? Thx Javier Somoza Oficina de Direccin Estratgica mailto:[EMAIL PROTECTED] Panda Software Buenos Aires, 12 48001 BILBAO - ESPAA Telfono: 902 24 365 4 Fax: 94 424 46 97 http://www.pandasoftware.es Panda Software,

Re: [PERFORM] fsync and battery-backed caches

2006-02-27 Thread Tino Wildenhain
Javier Somoza schrieb: Hi all Is it secure to disable fsync havin battery-backed disk cache? Thx No. fsync moves the data from OS memory cache to disk-adaptor cache which is required to benefit from battery backup. If this data is written to the

Re: [PERFORM] fsync and battery-backed caches

2006-02-27 Thread Jim C. Nasby
On Mon, Feb 27, 2006 at 11:12:57AM +0100, Tino Wildenhain wrote: Javier Somoza schrieb: Hi all Is it secure to disable fsync havin battery-backed disk cache? Thx No. fsync moves the data from OS memory cache to disk-adaptor cache which is

Re: [PERFORM] fsync and battery-backed caches

2006-02-27 Thread Bruce Momjian
Jim C. Nasby wrote: On Mon, Feb 27, 2006 at 11:12:57AM +0100, Tino Wildenhain wrote: Javier Somoza schrieb: Hi all Is it secure to disable fsync havin battery-backed disk cache? Thx No. fsync moves the data from OS memory cache to