From: Adriano d. S. F. <adr...@gm...> - 2011-10-25 10:03:55
|
On 25/10/2011 07:56, Paul Reeves wrote: > On Tuesday 25 October 2011 at 11:12 marius adrian popa wrote: > >> In other words: if you use Ext3 and you note performance regressions >> with this release, try disabling barriers ("barriers=0" mount option). > I can understand doing this for routine desktop work. It does make a > difference. But for a database server? The problem is that the old behaviour > was the wrong behaviour. Letting the hard drive re-order page writes > completely negates the efforts firebird makes to ensure pages are written in > the correct order. > > Let consider ext3/4 filesystem with barriers enabled, then: 1) FW=ON - each page written by Firebird goes to disk immediately, in the order issued by Firebird 2) FW=OFF, and use fsync on COMMIT - pages will not be reordered, and when COMMIT happens they will be written to disk in order Is this wrong? What's then the advantage of (1), since it's much slower approach? Adriano |