Hardware Requirements.

[rabbie]

Greetings all,

I am setting up Scalix for one of my clients and they have the following requirements:

1) Host many domains each with several email address
2) We expect to have about 50 email addressed on about 25 domains in the first 6 months and at least %25 increase every 6 months.

My question is, What sort of hardware should I be looking at for this project?

Is say, one XEON machine with 2GB of ram and say 120G SCSI RAID1 good enough for a year or two ?

Thanks.

Rabbie.

[kanderson]

When you say 25 domains, I read that you're looking to use Scalix for hosting email as an ISP, or similar.

You'll have some issues with that. They aren't insurmountable, but they do exist. Shared Addressbook being one. Every user will see every other user. They are not limited to a particular domain.

In terms of Hardware; if we simply ignore the potential issue above; 200 users is nothing. I think the Hardware you're talking about is more than adequate. I generally size HDD so that there's 2 Gigs per mailbox, but you can certainly limit your users to less. HDD IO will be your biggest limitation. SCSI is good, as is Mirroring.

RAM will matter significantly, and you've got plenty. Processor will matter the least. Any more or less current machine will be fine with 200 users.

[rabbie]

Thanks kanderson...

Just a question; aside from the address book issue you outlined, exacly how many mailbox's do you think this box can handle? Not taking into account space limitations, but refering more to load requirements??

Thanks again for your help.

Rabbie.

[burhankhalid]

It is difficult to answer the question because you would have to take into account how many concurrent users are on the box.

Your biggest issue (as pointed out earlier) will be RAM as Scalix is not that CPU intensive. For best results, I would recommend putting the SWA component on a separate machine -- if there are a lot of SWA users, then your machine might take a lot of RAM thrashing (as is the case in my situation) because of the memory requirements of Tomcat.

Its difficult for me to say as I don't run a very large user base, but in my experience, you should be able to support between 1 and 3 K accounts on that box.

[rabbie]

Thanks heaps for your input Burhankhalid,

The customer is opting for a dell server with 4GB of ram so that should be great

Rabbie.

[kanderson]

I built a scalix box yesterday.

It's a P4 2.6 with 1792 megs of RAM and software RAID between an IDE and a SATA drive. So obviously not ideal. It's just a desktop.

I was able to pump about 14000 (14 thousand) messages per hour through it, each approximately 1K in size. It did fall behind if things like logging, or anything else were turned on, but otherwise, it did OK. Utilization was obviously very high. It's not sustainable for the long term, but it could easily handle spikes into that range for short periods.

When I went for 1 message per second, utilization was very low, and there were zero issues with delivery.

You're talking about a far better box. It's hard to say what the limits will be. We have an office where a few graphic people send 50-70 meg attachments back and forth all day over IMAP connections on their MACs. They have a very busy box. On the other hand, we have a box with 500 users that has almost no load. Perhaps 0.03 utilization.

My experience is that IMAP connections (which includes the web) will tax a box far more than POP or MAPI connections. If you have POP or MAPI, I would expect you to get well into the thousands of users before you had any real concerns. But obviously, that will depend on how it's used, and what the volume of mail is.

If you're hosting, limit people to POP, and you'll be able to handle thousands of users.