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Thread: [SOLVED] Real World Sizing/Hardware Requirements

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    Default [SOLVED] Real World Sizing/Hardware Requirements

    I'm not sure if this is the right area for the question, but here goes my first post!

    I have a client that has been trying different linux based systems of and on to upgrade their existing mail server. The stats they would be running is 3 domains, 5000 users with around 2000 using the webmail interface and 3000 using pop3. Although the 'collaboration' features are nice they would not enable them. They are mainly looking at just MTA(spam and virus as well)/webmail. Currently they are using a qmail/mysql solution for their existing MTA and Atmail(buggy at best) for a webmail interface.

    I've done some testing in house here with my clients data with the opensource version and with all services on a single Dell PE1950(4gb mem, duo core dual processor) and everything installs/setups/testing migrations with little to no hitch. Its a great product! But the memory utilization has me concerned. After a day or two I drop from 3Gb of free memory down to 1Gb. Only thing I'm doing is just internal testing, config changes and transferring mail with pop2imap/imapsync from their existing server to this server.

    Reading the documentation a multi server environment sounds like just as much of a breeze as a single but with the clients needs and using similar Dell servers. How many boxes would be advisable. Currently the client does not have a SAN or any other shared storage nor do they want to take that large of a jump. But they wouldn't be opposed to go to a 2-6 server setup if its justifiable to gain additional growth, reliability and availability. Just curious as to what others have ran into with over 2k users.

    Thanks in advance for bearing thru my long drawn out 1st post!

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    What type of limits are placed on the accounts? Filesize and storage quotas?

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    Right now they are configured for 50MB quota with email sending of 50MB attachments. Their current box is running uvscan for local mail sent out for virus detection but they currently are outsourcing complete spam/virus protection from a third party device which would remain for the front line defense for all internet inbound email to anyone at the new server.

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    Default lowballing the budget.

    I run ibm x3650's here. While I do not have the numbers you have. Ideally you need a 64bit OS [I use Centos 5, but you probably want a supported os such as RHEL]
    So...Say for you start if you can do it [economically speaking, i haven't had a decent budget since I worked for Texas Instruments in the 90's]
    @80K worth of hardware.
    5 of your favorite server boxes, laid out with 8GB of RAM...RAID10 15K drives.
    Should be able to handle your needs. May also want to store the backups other than tapes to a MSA20 [not selling hardware, just saying how i do it]
    I have not played around with the clustering features all that much, but it is definitely cheaper than going with Exchange 07 or any self built LDAP/Cyrus/Postfix solution. Also with your SPAM solution, you will see less overhead on spooling, so you may be able to get away with 6GB of RAM...

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    Quote Originally Posted by tikitaru View Post
    After a day or two I drop from 3Gb of free memory down to 1Gb.
    How are you determining "free" memory? Don't just look at the "Free" field in top, as that is very misleading. Linux memory management is very different from other OSes. All available memory (ie not currently in use by a process) is used as a file system/data cache. As processes need more memory, data is pushed out of the cache and the memory assigned to the process.

    And swap usage isn't a good indicator of a lack of memory either, as the Linux kernel will write things out to swap even when there's lots of memory available.

    You have to look at the Inactive, Free, Cache, and Buffer fields in Top. When Free, Cache, *and* Buffer all get close to 0, only then are you in a memory crunch.
    Freddie

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    Quote Originally Posted by liston13 View Post
    I run ibm x3650's here. While I do not have the numbers you have. Ideally you need a 64bit OS [I use Centos 5, but you probably want a supported os such as RHEL]

    So...Say for you start if you can do it [economically speaking, i haven't had a decent budget since I worked for Texas Instruments in the 90's]
    @80K worth of hardware.

    5 of your favorite server boxes, laid out with 8GB of RAM...RAID10 15K drives.
    Should be able to handle your needs.
    Wow, talk about overkill. $80,000 to support 5,000 mailboxes? With only 50 MB of disk quota each? That's only 250,000 MB or 250 GB of disk.

    You could support this on a single 2U server with dual-dual cores or dual-quad cores and 8-16 GB of RAM, with 6 500 GB HD. If you want more disk space, then go to a 4U or 5U rackmount with more harddrives (our largest storage server has 24 drive bays, 12 populated, with 6 TB of disk available).

    Our largest server is a dual-dual core AMD Opteron 2.8 GHz system (4 cores total) with 8 GB of RAM and 12x 450 GB HD attached to a 3Ware Escalade 9650SX-12ML PCIe RAID controller. 3x redundant power supply, with network management card, and PCIe quad-port Intel gigabit NIC. Just slightly more than $10,000 CDN.

    $80,000 is a bad budget for a single project's hardware?? Man, I'd love to work where you work. $80,000 is our server/desktop/network hardware budget for the entire year!
    Freddie

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    I really appreciate everyones input on this. Below is a graph of this week but have been swept away on another fire the last two days so sunday was the last day I ran imapsync or did anything of noticable processing which like I said there are currently no active connections besides some spam lists I signed up some test accounts to.
    Attached Images Attached Images

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    meant 8K. Trust me...i know about budgets all too well.
    I learned in MBA school...
    Cheaper, Better, Faster....pick two.

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    Quote Originally Posted by liston13 View Post
    meant 8K. Trust me...i know about budgets all to well.
    I learned in MBA school.
    Cheaper, Better, Faster....pick two.
    lol you had me concerned with the 80k figure as well. The box I'm running this on now is a dual-dual core 2.0Ghz with 2x4mb cache and 4GB memory and 4x73GB 15k harddrives and paid a little under 3k for it. I know most of the cost was the 'Dell' namebrand and warranty. I bought 2 for this project orignally, one for a cold standby but I'm sure I can stretch another 2 or 3 out if need be.

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    Quote Originally Posted by liston13 View Post
    meant 8K. Trust me...i know about budgets all too well.
    Whew! That makes a lot more sense. Thought you worked for somewhere that considered $100,000 for a project to be small potatoes.
    Freddie

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