[Dovecot] Large folders and timeouts

[Simon Waters]

On Thursday 11 May 2006 06:27, Alan Premselaar wrote:
>
> 1) NFS is typically slow... definitely slower than local storage,
> although if it was typically *THAT* slow, it wouldn't be a viable
> storage solution for a majority of places that use it.
>
> 2) when dealing with any filesystem, typically write speeds will be
> slower than read speeds.  the fact that the timeout is ocurring during a
> COPY makes me think your problems may be related to write speeds.

NFS also defaults to synchronous operations. 

I remember one site where I spent a long time understanding exactly how the 
NFS, and disk, writes were synchronised.  In this case I was able to get 
write performance from pitiful to near wire speed, and if I'd had modern 
filesystems I'd have been able to get that without paying such a huge price 
in leaving data cached in RAM when it should have been safely on disk.

The most obvious sign of synchronous write issues with such systems is disk 
thrashing, which can usually be seen by watching the disks activity lights, 
or listening to the disk drives.