RE: [Exim] Exim and NFS

Francisco wrote:
> I'm sure this subject has been discussed a million and a
> half times, but, here I go anyways....
>
> We have an Exim configuration with 4 nodes which mount the
> main mail storage off of a relatively new system (Dell 2650)
> running RAID-5 and 4 drives.
>
> What we're finding as strange or out of the ordinary is the
> ratio of bandwidth being used between the "client facing"
> and "nfs-server facing" interfaces.
>
> We see about 7Mbps on the client facing side but nearly
> 70Mbps on the NFS side.
> Is this ratio normal?
>
> Maildir is being used.
> We use LDAP as well (slapd/OpenLDAP).

This makes sense. The client end of things cares not for file locks, etc...
It just obeys (hopefully) the SMTP/POP3/IMAP protocol which is, at least, in
the case of POP3 for example as simple as "retr 1" to get the first message.
Compare this to the possible bandwith used to interact at a filesystem level
across TCP/IP and that may very well explain the bandwidth difference.

Don't take my word for it though - if you're curious, run tcpdump on both
interfaces and coordinate it with a simple test or two, then examine the
differences (dump to a file, you can simply compare file sizes for a rough
guestimate).

Eli.