On Jul 7, 2011, at 9:47 AM, Trond Myklebust wrote: > 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. We shouldn't allow such low settings. > Secondly, the _other_ fix for this problem is to fix the documentation. How is the documentation incorrect? We do not want any kind of back-off for stream transports. -- Chuck Lever chuck[dot]lever[at]oracle[dot]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
