Re: Hashed mailboxes ?

[sterling@netapp.com (Bruce Sterling Woodcock)]

>   The common way to solve this is to put mailboxes into user home
> directories.

Yes, although there are a lot of mail programs out that that have to be
modified; some don't even support $MAIL or $MAILDIR variables..

>   Also, I did some tests on this, I found no problems with mail spools
> with 30,000+ mailboxes.  The time to open one file in a directory with
> 30,000 other files, is not that much slower than a directory with a 1000
> files in it.  This is somewhat os dependant though.

It does depend highly on OS, but also on the load of the server.  A big
problem is that the mail directory is scanned *constantly* at large sites...
your shell has mailcheck, your biff, your mail program that you run all the
time, your MUD client you have running in the other window, etc.  The
larger that directory is, the longer it takes to search, and a larger
directory also usually means more clients searching it...

Not to toot my own employer's horn (I actually experienced this at a
previous company, so I believed in the solution before working here) is
that if you store your email over NFS, consider getting a Network Appliance
fileserver for the mail spool.  The software has had special optimizations
for large directory operations since OS 2.1; the benefit to mail spools is
obvious, but also for news filesystems as well (some of those groups get
quite big).  There is a good technical paper on the problem as well as some
qualitive results from the speed-ups that were implemented; you can find it
at htpp://www.netapp.com/technology/level3/3006.html.

Bruce

-- 
Bruce Sterling Woodcock ------ Systems Administrator ][ sterling@netapp.com
Network & Systems Administration - Network Appliance ][ sterling@netcom.com