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 *still* have unexpected power failures. The 'master' for distributed.net had exactly that happen recently; the two breakers feeding it (from 2 seperate UPS's) failed simultaneously. In a nutshell, having a server on a UPS is notthing at all like having a BBU on the raid controller: commiting to the BBU is essentially the same as committing to the drives, unless the BBU runs out of power before the server has power restored, or fails in some similar fasion. But because there's many fewer parts involved, such a failure of the BBU is far less likely than a failure up-stream. So, if you want performance, get a controller with a BBU and allow it to cache writes. While you're at it, try and get one that will automatically disable write caching if the BBU fails for some reason. On Tue, Feb 28, 2006 at 06:27:34PM +0100, Javier Somoza wrote: > > 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 it's about 3x longer than the email you > > actually sent. > > -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
