The total timeout for a "mount" attempt to a non-responsive server will always be a multiple of the time a single mount attempt in the kernel takes, which for TCP defaults to about 4 minutes. The documentation for the "retry" option seems to suggest that this can be used to set a maximum but it really sets a time after which to stop retrying. The total can be as much as "retry" plus the time for a single attempt. So clarify the documentation a bit, and also note that retrans defaults are different for UDP and TCP: #define NFS_DEF_UDP_RETRANS (3) #define NFS_DEF_TCP_RETRANS (2) Reported-by: Howard Guo<hguo@xxxxxxxx> Signed-off-by: NeilBrown <neilb@xxxxxxxx> --- utils/mount/nfs.man | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/utils/mount/nfs.man b/utils/mount/nfs.man index e541cdc95cb1..a0f790a5961b 100644 --- a/utils/mount/nfs.man +++ b/utils/mount/nfs.man @@ -158,8 +158,8 @@ up to a maximum timeout length of 60 seconds. The number of times the NFS client retries a request before it attempts further recovery action. If the .B retrans -option is not specified, the NFS client tries each request -three times. +option is not specified, the NFS client tries each UDP request +three times and each TCP request twice. .IP The NFS client generates a "server not responding" message after @@ -391,6 +391,16 @@ is 2 minutes, and the default value for background mounts is 10000 minutes If a value of zero is specified, the .BR mount (8) command exits immediately after the first failure. +.IP +Note that this only affects how many retries are made and doesn't +affect the delay caused by each retry. For UDP each retry takes the +time determined by the +.BR timeo +and +.BR retrans +options, which by default will be about 7 seconds. For TCP the +default is 3 minutes, but system TCP connection timeouts will +sometimes limit the timeout of each retransmission to around 2 minutes. .TP 1.5i .BI sec= flavors A colon-separated list of one or more security flavors to use for accessing -- 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
