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Subject: Re: SCSI, U2W in particular?, and poor performance...
From: Rich Graves (rcgravesbrandeis.edu)
Date: Sun Mar 05 2000 - 16:38:59 CST

Justin Robertson said:
>
> Prehaps you'd like to tell me why sendmail outperformed postfix on the
> SCSI machine then? hmm?

We don't know for sure what your syncing behavior is, but regardless the
default monolithic sendmail installation does less disk I/O than postfix.
To get sendmail to behave like the default postfix installation you'd set
in sendmail.cf

# default delivery mode
O DeliveryMode=queue
# queue up everything before forking?
O SuperSafe=True

A high-volume production sendmail installation would probably set these
anyway.

I run production mail systems with Linux, but I don't trust ext2fs. I sync
writes and gain the speed back by spending money on hardware RAID with
battery-backed cache. Given limited local resources and expertise (it's
much easier to find Linux admins willing to accept .edu pay scales than
UNIX admins), that tradeoff seems better than supporting another OS. Plus
hardware RAID isn't a bad thing to have. I used to try to run maildir on a
NetApp but had too many problems with Linux NFS.

If your hardware is fixed, I think your best bet would be to invest some
time learning Open/FreeBSD. Or just live with the risk. If your customers
and boss are used to Windows, they'll be forgiving of the occasional mail
lossage in case of catastrophic failure. It's not like it'll happen every
day. It takes real UNIX or mainframe experience to know that such lossage
need not be accepted. 

-- 
Rich Graves <rcgravesbrandeis.edu>
UNet Systems Administrator