System Bottlenecks

[Errol Neal]

At 04:47 PM 9/2/2003 +0100, you wrote:
>The best I/O improvement is by making sure you've got plenty of RAM and
>putting the MailScanner work directory in tmpfs (not either of the mail
>queues though!)

That is a bit scary for us. Unpacking messages in a memory based
file  system could be catastrophic. *Shudders*. Too scary to even think
about it if for example,
MailScanner dies and leaves a bunch of mail in the tmpfs and we unknowingly
reboot the system... for us.. instant law suit.
Can anyone explain how this works? Does MailScanner unpack messages 1 at a
time, does it unpack all the messages bulky in this directory?

>Personally speaking ufs sucks and anything FS intensive struggles on
>Solaris (in fairness my experience is with low end machines, E250 and
>lower).  You'll get more bang-per-buck using linux on Intel.  Where
>Solaris excels is at the high end and I can't see why anyone would need a
>high end server for a mail load of only 15-20k.

We are using the lower end Netra T-1 and V Fire 100 (I think). Turning on
logging increases performance dramatically. Compared against linux using
XFS logging on ultra 160 drives, the performance is almost equal.

>If you've got the money for Sun hardware buy Intel and get an extra box
>for redundancy/ load balencing!

Lower end sun models are actually quite inexpensive these days. 550MHZ cpu,
512 RAM, two nics and 40GB ide for less and 1K US is not too bad.

We actually have 3 systems deployed at the moment, each system handles
about 15-20K messages a day, and that varies. I guess what I am trying to
achieve as I said earlier is a strategic
investment of dollars into what will make the difference most dramatically.
For example, if 1 gig of ram will improve the systems performance over our
current 512MB Ram in a much greater way than
deploying SCSI based /var/ slices, I will put my money in the RAM and stick
to my IDE disks. This is what I need to know.


Errol Neal, Systems/Network Administrator
eneal at enhtech.com
Enhanced Technologies Inc.
http://www.enhtech.com
703-924-0301 or 800-368-3249
703-924-0302 Fax