Voicemail - max 13 concurrent calls

Hi, I plan to use asterisk as a voicemail.
Right now it is installed on a Pentium 3 750 MHz 256 MB RAM (old DELL desktop…:smile:). I didnt want to use high performance machine, because in the end we want it to run on EPIA (VIA mini ITX with 1GHz CPU).

While testing voicemail with SIPP (2 cps, call time 15 s), I could only reach 13 concurrent calls (I’ve tried different codec configurations and voicemail msg format). When the cap was set (in SIPP) to max 13 calls the 500 messages (Internal serwer error) were quite rare, but when I tried to go beyond 13, Sipp was flooded with them. In the mean time, the average CPU ussage was 2% (max. 8%) and there was about 50 MB RAM still free.

I wondered if the cause was HD bottleneck (writing messages to disk) but there should be a difference between saving voicemail in uncompressed .wav and .gsm - the first one produces larger files.

Does anyone have any suggestions?