hardware requirements

Discussion in 'General' started by bbob, Aug 12, 2010.

  1. bbob

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    I am looking to install elastix on a vps server.

    Have about 15 did trunks, 20 extensions, maximum 4 outgoing calls at the same time.
    Mainly using G711 codec (G722 optional)

    Looking at a vps 256-512 mb, 1 core, 10 gb hdd space

    Would this be enough to run elastix ?
     
  2. Awesomo

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    With 512mb ram and a decent core off a modern quad core xeon WITH the bandwidth to support it all, yes. BUT BEWARE, you will have hell on earth trying to get the timing correct. Do you know the underlying technology being used to create that VPS? ESXi, XenServer?, Xen? Etc... Timing for voip in virtual machines is no picnic. Which translates to choppy sounding calls for you, the end user.
     
  3. bbob

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    The info I got the VPS runs under ZEN.
    System I am looking at has failsafe. HDD runs on a SAN attached to a clusster of computers.

    The contract is monthly anyhow so if it doesn't work I can cancel it.

    Is there any way I can test to see if I get choppy calls. Saw somewhere on the net a utility or command that would test how many simultanious calls I can make.
     
  4. Awesomo

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    If they are using xen, Elastix should have a kernel ready to go for it.

    You can test if you'll get choppy calls by calling people :)

    dahdi_test from terminal. It will give you a series of percentages. Should any drop below 99.94. You most likely will have some choppy calls. (You may get clear calls with slightly lower results, but I won't guarantee anything, let your ear decide.)

    You shouldn't have to run a speed test (you should at your office though). Data centers will price their products with bandwidth included. They might say 5mbit unmetered or 1500GB transfer on 100mbit link. Then all you have to do is a little math. Keep in mind you will need to double all of these numbers. You will need the bandwidth to call in to the server, and then the bandwidth for the server to send the call out the sip/iax2 trunk.

    87.2kbit is one phone call with the g711 codec.
    5mbit = 5000kbit
    5000/87.2=57 simultaneous calls. (Although I'd chop a few from that number, you never want to come close to saturating a connection. I'd say max 50 calls to be safe. Once your connection is saturated, all 57 calls will go to hell quickly.)

    Billed per GB is a little different. You need to calculate total bandwidth usage. An hour long call with g711 will only take 39,240kbytes of transfer.

    (87.2 (87.2 kbit/s a g711 call uses)*3600 (3600 seconds in one hour))\8 (8 kilobits in 1 kilobyte)=39,240

    If you want to see if your isp is lying, ask if they have an iperf server or try to locate an iperf server near the server, then you can run iperf from the linux terminal.
     
  5. bbob

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    Thanks for the info.

    As I have little knowledge of linux and installing they will install it for me. They are running centos as standard. Is there a link where they have a elestix version for working under zen or will any version work ?

    Will try it end of next next week and let you know if it works fine or not. Will start with using it for outgoing calls on 1 phone just to test. Can call me other voip phone also on an astersik based bpx to see it there are no problems.
     
  6. jman

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    I just setup my elastix with www.rentpbx.com. They have elastix 1.6 and 2.0 with proper dahdi driver. I have no problem so far. I am paying $19.99 a month. I found about them from a discussion forum post at dslreport.com. I hope this helps. Hopefully, I am not too late. I just found out about them few days ago.
     
  7. bbob

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    Stumbled accross them some time ago. Problem is than I am in Europe and would like to have an european sever to keep ping times down.

    I am now on a cloud vps with failoversystem, 1 core, 512 mb and 20 gb hdd and this seems to work fine for now.
     

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