NFSv3, ZFS, 10GE performance

[Bob Friesenhahn]

On Wed, 28 Mar 2012, Rick Macklem wrote:
>>
>> Hopefully, readahead doesn't kill performance for smaller files.. :-)
>>
> Well, readaheads only happen if the file is large enough for the readahead
> to be before EOF. As such, they just won't happen for small files.

The real problem is for applications which do a seek and a new read 
prior to consuming all the data which is being read ahead on its 
behalf.  This results in read amplification and increased latency for 
the next seek+read.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/