Re: NFS rename sometimes hangs for 15 seconds after upgrade to Debian 8
On 2015-09-25 10:11:10 +0200, Peter Ludikovsky wrote:
> My guess is:
> Due to the rather large wsize/rsize, the clients create a rather large
> attribute cache. As a result, when you cat a file on the second
> machine it updates the atime in the cache, but doesn't yet transfer
> that information to the server. When you do the mv on the first
> machine, the client tries to get the current attributes on the files
> involved, which prompts the server to wait until the second client
> runs into some kind of timeout and updates the attributes. Only then
> is the second file "unlocked" to be overwritten.
>
> Further proof of that: when setting noatime as a mount option, instead
> of noac, there's also no delay on the mv.
Thanks for the explanations. But the second client, though it doesn't
update the attributes immediately, seems to do it quickly when asked
by the server, otherwise the problem would also be visible on Debian 7
machines. I think that on Debian 8, when the rename cannot be done
immediately, the client retries after 15 seconds instead of retrying
earlier.
Is this related to the following patch?
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8478eaa16e701ecfe054b62ec764bc1291b79e19
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Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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