On Sat, May 30, 2009 at 11:02:47PM +1000, Greg Banks wrote: > On Sat, May 30, 2009 at 10:26 PM, Trond Myklebust > <trond.myklebust@xxxxxxxxxx> wrote: > > On Sat, 2009-05-30 at 10:22 +1000, Greg Banks wrote: > >> On Sat, May 30, 2009 at 3:35 AM, Trond Myklebust > >> <trond.myklebust@xxxxxxxxxx> wrote: > >> > On Fri, 2009-05-29 at 13:25 -0400, Brian R Cowan wrote: > >> >> > >> > > > > Firstly, the server only uses O_SYNC if you turn off write gathering > > (a.k.a. the 'wdelay' option). The default behaviour for the Linux nfs > > server is to always try write gathering and hence no O_SYNC. > > Well, write gathering is a total crock that AFAICS only helps > single-file writes on NFSv2. For today's workloads all it does is > provide a hotspot on the two global variables that track writes in an > attempt to gather them. Back when I worked on a server product, > no_wdelay was one of the standard options for new exports. Should be a simple nfs-utils patch to change the default. --b. > > > Secondly, even if it were the case, then this does not justify changing > > the client behaviour. > > I totally agree, it was just an observation. > > In any case, as Christoph points out, the ext3 performance difference > makes an unstable WRITE+COMMIT slower than a stable WRITE, and you > already assumed that. > > -- > Greg. > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
