On 15 February 2006 05:12, Adam McDougall wrote:
Does anyone have any tips for tuning a netapp (and/or clients) for nfs access to Maildir email folders?
Not specifically for Maildir folders, however I have recently read through the following document:
http://www.netapp.com/library/tr/3183.pdf
I've adopted the various tuning options as per that document such that my Linux clients now mount the various exports with options:
noatime,rw,hard,intr,addr=<ip_address>,rsize=32768,wsize=32768,tcp
We recently took a new customer-facing system live and found that, whilst using UDP with no real tuning, we were getting errors of the form:
kernel: RPC: error 5 connecting to server <ip_address> kernel: lockd: couldn't create RPC handle for <ip_address>
on the clients. We also experienced some slowdowns and stutters on the clients when under load, even when re-reading the same file over and over again - indicating network-related problems (although it's a clean gig ethernet LAN). Switching to TCP made it all so much better in termns of performance.
In terms of MUA performance I'd be wary of letting any old MUA load up "several tens of thousands" of headers as you could well find yourself experiencing heavy IO on the client running the MUA at that point due to paging or swapping. I know I experience slowdowns on my old-fashioned personal mail system which runs mbox format (at the moment) on an EXT3 filesystem, but it's simply a function of the mbox being so large that it's fragmented on disk and that the client MUA I run only has 256MB of RAM and has to do a lot with it! In tests you might find you need a lot of RAM on a system doing nothing but IMAP access in order to keep a level playing field.
I'm not entirely sure you could do that much tuning on the filer which would be specific to Maildir format itself, to be honest.
Graeme