I mostly concur with Andrew here, but let me add some specifics.
1) *Memory* - for the 5000 series of chips using FB-DIMMs you need 4
total sticks to max out the memory bandwidth. 4 gets you twice the
memory bandwidth of 2, though you can use just 2. The real-world
benchmarks show maybe a 5% improvement, though this depends largely on
what you are doing. I'm not aware of any advantage to getting faster
memory as I believe these systems will run the memory at the speed
dictated by the processors. The amount of memory for this particular
application will depend on how many cores you have. I would do 2GB with
4 cores, and 4GB with 8 cores, but only if you are going to be pushing
hard on them (and you probably won't be).
2) *CPU* - You should be fine with just 4 cores, in fact Windows will
not likely be able to max out 8 cores with Declude due to heap issues
(limitations in memory allocations). I run 8 x 1.86 Ghz cores and I
start getting a lot of errors if I press the system to 100% from
Declude, which with my config is somewhere between 150 and 200 messages
being scanned concurrently. How much load per message will depend on
what you are running in your Declude config. Mine is rather heavy,
though I still couldn't get more out of the server in terms of total
utilization due to the heap issues, though the messages would process
more quickly with a lighter config. So I would guess that with 4 x 2.33
Ghz cores, you could do about 100 concurrent messages. Also take note
that there are lower wattage quad-core Xeons out now that begin with
"L". These run about 50 Watts instead of 80 Watts for the standard
quads. This does add up, especially when you consider that cooling and
other supportive processes will at least 1 to 2 times that amount of
power for what the server actually uses. If you pay your own power
bills, the "L" series processors should pay for themselves.
3) *Disk and RAID* - SATA is the way to go. Try to stay away from the
2.5" drives if you can. Modern SATA controllers can handle RAID 5
without a bottleneck, and on a 4 drive system with a modern RAID
controller, RAID 5 will definitely outperform RAID 10. I recommend
3Ware 9550sx controllers, but you should be safe with any SATA II
controller that supports a battery backup for the cache. I would stay
away from zero-channel RAID cards, and definitely anything that is host
RAID or software RAID because they are much more likely to require
physical intervention in the event of a drive failure. There is no need
to separate the OS onto a different drive system for this purpose. I
would get 250 GB drives since they will initialize faster and the extra
space likely isn't needed. I run my 8 core system on a 4 drive RAID 5
array with SATA II drives and it works great.
4) *Pre-scanning Gateway* - Most Declude servers will save between 30%
and 50% CPU utilization by adding an Alligate server in front of it
(much more if you have catch-alls or aren't doing address verification
at all). You will also block significantly more spam that way,
especially the zombie stuff. I have helped many set up Alligate, and we
can even host a backup server or set something up as a test if you were
interested. Alligate doesn't require a lot of processing power, though
the system needs to be a stand-alone system. Even a single-core server
with a single drive would handle this great, though it makes sense to
have a backup. Note that out of the box Alligate won't do near what it
can when configured by an experienced administrator, and you can block a
ton of spam and other attacks with virtually no false positives
(definitely +99.99% accuracy is possible while rejecting over 80% of all
connection traffic). There is another hidden benefit to using Alligate;
many of the killer messages that can affect both Declude and IMail are
stopped by a properly configured Alligate pre-scanning gateway, and
virtually all of the automatically-spreading viruses too.
Matt
Colbeck, Andrew wrote:
Hello, Serge.
I'm happy to chime in here, but let me start off with saying that you
will get divergent opinions here, and that nobody will be absolutely
right, as our answers are coloured by own experiences, and each
implementation is unique.
I'll also start off with asking you for your current and your intended
message volumes, general architecture and software mix. Answering these
details will help you keep the arguments comparing apples to apples
because what is true for one respondent with low volume will not be true
for another respondent with crushingly high volumes!
My answers:
1- Memory
I used to agonize over the making the exact right decision regarding
slots, interleaving and multipliers; my truth *now* is that these are
tweaks that make 2% to 6% of the raw memory speed in benchmarks and that
it makes precious little difference in the real world for, say, an email
server.
Memory is relatively cheap; buy as much as you want as long it's from a
name brand like Kingston, avoiding for example buying it from HP (the
days are long gone where Compaq would tell you to remove 3rd party RAM
to get support from them).
2- Disk technology
Yes, my truth is that your fast servers need SCSI, SAS or a SAN based on
those technologies. For bulk storage, choose SATA to save you a lot of
money on back-end servers.
In addition, buy a battery backed RAM cache controller for your RAID
controller; this will enable write-cacheing on the RAID controller. An
HP RAID controller will not assume that you have a battery backed UPS,
and will not cache writes without this add-on. The throughput of your
write operations are critical for a busy email server. If you buy an HP
Proliant server based on SAS with 6 internal drives you will also need a
second controller cable.
3- Disk layout
Don't go cheap and use a single unprotected drive for any purpose. I
used to like that format too, but my uptime and remediation time is more
important than the cost of the drive technology.
The layout you've described, it's good. Put the swap file on the System
drive.
Other commentary:
If you use HP, you really really really should use their Firmware Update
and SmartStart install CDs. Download the current version rather than
using the one that comes in the box. Also update your HP Insight Manager
once the OS is installed, and set up your HP Insight Manager to send
email alerts to a generic helpdesk account within your tech support team
and *never* to just one staff member.
The cefib.com domain is an ISP; I'd actually recommend TWO servers that
are less expensive instead of one large one for your environment.
The first server: As an antispam gateway for your inbound mail.
The second server: As your mailbox store and for your outbound mail.
Put monitoring software on each, watching the other server and your
other connectivity as required.
Andrew.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Serge
Sent: Friday, December 21, 2007 1:41 PM
To: declude.junkmail@declude.com
Subject: [Declude.JunkMail] Hardware Upgrade
Hi
We are planning a hardware upgrade for february, after 5
years on the previous ML370G2
We will buy a 2slot QuadXeon Motherboard, 1.333FSB, and
2x2.33GHz QuadXeon, 2GB DDR2 and have some technichal
questions for the resident techies
1- Should we get the fastest memory available, or should the
memory speed be a divider of 1333 or 2.33 ?
2- Does a mail server really need SCSI or SAS @15K/Minute ?
or regular SATA @ 7K or 10K enough ?
3- We are planning on using :
2 HD in Raid1 for System
2 HD in Raid1 for Mailboxes
2 HD in Raid1 for Spool
Where should we put the virtual Memory ?
Or, is it better to have
2 HD in Raid1 for System
2 HD in Raid1 for Mailboxes
1 HD Spool
1 HD for VM
You all have a good weekend and a merry christmas next week
Serge Dergham
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