[asterisk-users] Server Setup Advice

[Gordon Henderson]

On Sun, 8 Mar 2009, Elliot Murdock wrote:

> Hello Gordon,
>
> Aside from alaw and ulaw, we also use G729.
>
> I am not that familiar as to how Asterisk converts PRI signals into
> coded format, but why wouldn't any transcoding be necessary for alaw
> and ulaw codecs?

It shouldn't have to convert them as they'll come in in ulaw or alaw 
already (depending on your country: ulaw for the US and Japan I think, 
alaw for most other places)

I guess you're using g729 for remote connections though. Always use ulaw 
or alaw for local/LAN connections when talking to a PRI. There was a paper 
published some time back which demonstrated 14 (I think) transcodes to 
g729 on a 1GHz processor. My own experience is that I can do 10 on simialr 
hardware without getting near 100% CPU, so a faster CPU with better MMX, 
SSE instructions, etc. ougut to do many more.

Gordon


> Regards,
> Elliot
>
> On Sun, Mar 8, 2009 at 8:52 PM, Gordon Henderson
> <gordon+asterisk at drogon.net> wrote:
>> On Sun, 8 Mar 2009, Elliot Murdock wrote:
>>
>>> Hello!
>>>
>>> There will be disk writing in these areas:
>>> 1. Logs
>>> 2. CDRs
>>> 3. MYSQL Call logs
>>> 4. Faxes and voicemail
>>
>> I'd not consider these to be a heavy load myself...
>>
>>> Also, there will be a lot of codec encoding/decoding from/to the PRI
>>> devices, which is my main concern with CPU load.
>>
>> Why are you transcoding? Are your extension users remote? If you set ulaw or
>> alaw to be the codec (depending on country) used by the extensions there
>> won't by any transcoding at all.
>>
>> Gordon
>>
>>
>>> Cheers,
>>> Elliot
>>>
>>> On Sun, Mar 8, 2009 at 7:56 PM, Gordon Henderson
>>> <gordon+asterisk at drogon.net> wrote:
>>>>
>>>> On Sun, 8 Mar 2009, Elliot Murdock wrote:
>>>>
>>>>> Hello!
>>>>>
>>>>> Oh, yes, I will be mirroring the harddrives in case of any failures.
>>>>>
>>>>> What is your opinion about using (software) RAID?  Do you think the
>>>>> overhead impacts performance too much?
>>>>>
>>>>> In an ideal situation, I would use hardware RAID, but that is not
>>>>> feasible right now.
>>>>
>>>> I've used Linux software RAID for over 10 years now. for me, it's my
>>>> first
>>>> choice.
>>>>
>>>> You shouldn't be doing many disk writes though - unless you're recording
>>>> all
>>>> calls or handling a vast amount of voicemail.
>>>>
>>>> And with modern hardware there shouldn't be issues that we had in the bad
>>>> old days - DMA, PIO, etc.
>>>>
>>>> There is a double on resources required to write a block to a software
>>>> RAID-1 (mirror) unit but in a modern system, you're not going to notice
>>>> it.
>>>>
>>>> And FWIW: I regularly have systems with 20-40 extensions running on a
>>>> 1GHz
>>>> VIA processor, so CPU wise, you've got more than enough - unless you're
>>>> transcoding
>>>>
>>>> Gordon
>>>>
>>>>
>>>>>
>>>>> Thanks,
>>>>> Elliot
>>>>>
>>>>> On Sun, Mar 8, 2009 at 4:26 PM, Jay Milk <ast-users at skimmilk.net> wrote:
>>>>>>
>>>>>> Elliot Murdock wrote:
>>>>>>>
>>>>>>> Hello Everybody!
>>>>>>>
>>>>>>> I am currently setting up an Asterisk server for medium to high load
>>>>>>> (approximately 20-35 concurrent phone lines).
>>>>>>>
>>>>>>> Do you think the following specs will sufficiently satisfy this
>>>>>>> system?
>>>>>>>
>>>>>>> CPU: XeonQC3220 2.4GHZ 8M
>>>>>>> RAM: 2X2GB/800
>>>>>>> Harddrive: 1X250GB
>>>>>>>
>>>>>>> I could add harddrives and partition them into /var and /log
>>>>>>> directories to help with diskdrive throughput.
>>>>>>>
>>>>>>> Thanks!
>>>>>>> Elliot
>>>>>>>
>>>>>>>
>>>>>> I'm sure this is common sense, but make sure you have a plan B for when
>>>>>> that HD fails.  It will.
>>>>>>
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