[Asterisk-Users] update - 512 Simultaneous Calls with Digital Recording

[Matt Florell]

Hello,

What happens a few weeks into this when you've fragmented the free
space on the drives by deleting files periodically and rewriting in
some places? The consistent performance of SATA drives goes down
dramatically when this happens, much more so than on a SCSI-based
drive system.

Also, you don't seem to take into account the read-write-seek time of
SATA drives into your calculations

Another thing to consider is that if anything else is being done on
these drives(like running Linux or Asterisk or anything else) the
write performance will also be effected.

MATT---

On 4/3/06, Isaac Xiao <isaac.x at kvbkunlun.com> wrote:
>
>
>
> Hi All,
>
>
>
> In previous mail lists, people talked about a solution to record large
> amount of simultaneous calls. And then it seems that RAM disk solution was
> the best choice due to the I/O bottleneck of Hard disk (System). Please find
> the previous discussion as follows:
>
> http://lists.digium.com/pipermail/asterisk-users/2005-October/120930.html
>
>
>
> http://thread.gmane.org/gmane.comp.telephony.pbx.asterisk.user/118497
>
>
>
> I noticed that an Intel server platform comes with 4 ports SATA-II RAID0/1
> controller. Please check this link:
>
> http://developer.intel.com/design/servers/boards/se7230nh1-e/index.htm
>
> SATA-II is 3Gps I/O. so I am thinking implement this solution for recording
> large amount of simultaneous calls. My proposed solution is:
>
>
>
> CPU: Prentium 4 Dual core 3.2G or higher
>
> RAM: 2G or more
>
> OS HDD: 2 x 80G SATA-II HDD for RAID 1 (for OS)
>
> Separate HDD for voice recording: 1 x 200G SATA-II HDD standalone
>
> Voice recording format: WAV
>
>
>
> I did a test on my Asterisk PBX. One leg of 61 seconds WAV voice recording
> use 947564 bytes of hard disk. I did an optimal estimate of numbers of
> simultaneous calls with 3Gps without thinking of CPU and system limitation.
>
>
>
> Two legs: 947564 x 2 x 8 = 1895128 Bytes x 8 = 15161024 bits
>
>
>
> 15161024/61 = 248541 bits/s
>
>
>
> So the number of simultaneous calls 3Gps I/O can handle:
>
>
>
> 3(Gps) x 1024(Mb/G) x 1024 (Kb/M) x 1024 (b/Kb) / 248541 = 12960 calls.
>
>
>
> 512 are far less than 12960. So I think the hard disk I/O should not have
> any bottleneck problem for 512 simultaneous calls.
>
>
>
> Welcome to add your comments, do test and give feedback.
>
>
>
> Cheers,
>
> Isaac Xiao
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