>>>>> "jc" == Jere Cassidy <[EMAIL PROTECTED]> writes:
jc> ... Backend network is a Netapp F230 that is handling the Maildirs.
jc> a) Almost all delivery (from sending client to remote client)
jc> takes 3 to 4 minutes. However, If I look in the receiving
jc> client's Maildir/new after the sending client sends the message,
jc> it is there in 5 to 10 seconds. Any POP3 connection simply does
jc> not notice the file is there even though it is present on all 4
jc> servers (via the Netapp, of course). Most likely this is the
jc> result of some caching that the front end servers are doing, but
jc> we haven't been able to track it down exactly.
You're probably being bitten by NFS attribute caching. Under Solaris,
the "actimo" option ought to be cranked down to zero if you want to
have new files be visible to other NFS clients immediately. See the
"File Attributes" portion of the Solaris mount_nfs(1M) man page.
Other OSes may or may not have knobs to tweak for NFS attribute
caching.
A good reference for this sort of thing is a paper from the USENIX
Symposium on Internet Technologies and Systems (USITS) Proceedings,
Monterey, CA, December 1997: "A Highly Scalable Electronic Mail
Service Using Open Systems" by Nick Christenson, Tim Bosserman, and
David Beckemeyer of EarthLink Network, Inc. The email servers at
EarthLink have been using NetApp fileservers for message storage for
years; the paper discusses the architecture, problems they
encountered, and solutions used.
-Scott
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Scott Lystig Fritchie, Minneapolis, MN
Professional Governing: Is It Faked?
