On Thu, 2011-07-07 at 18:11 +1000, Max Matveev wrote: > I've had to look at the way NFS/TCP does its timeouts and backoff > and it does not make a lot of sense to me: according to the > following paragram from nfs(5) on Fedora 14 (I'm using Fedora 14 > because it has more text then the same page in nfs-utils): > > timeo=n The time (in tenths of a second) the NFS client waits > for a response before it retries an NFS request. If this > option is not specified, requests are retried every 60 > seconds for NFS over TCP. The NFS client does not per‐ > form any kind of timeout backoff for NFS over TCP. > > but if I try the mount with timeo=20,retrans=7 then I'm getting > retransmits which are 2, 4, 6, 8, 2, 4, 6, 8 seconds apart, i.e. > there is a) linear backoff and b) the backoff is not long enough to > let the complete sequence of 7 retransmits run its course. Sigh... Firstly, 2 second timeouts are complete lunacy when using a protocol that guarantees reliable delivery, such as TCP does. Anyone who tries it deserves exactly what they get: poor unreliable performance. Secondly, the _other_ fix for this problem is to fix the documentation. Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
