This load test of IP PBX Asterisk running on HP Microserver Gen8 was conducted by SoftBCom (www.softbcom.ru) Loway Wombat Dialer was used for load generation Direct load test of IP PBX Asterisk on HP Microserver Gen 8 discussed here shows that it can support more than 1000 concurrent calls

1. Load test of IP PBX Asterisk
installed on HP Microserver Gen 8
Direct load test of IP PBX Asterisk
on HP Microserver Gen 8 shows that it can support
more than 1000 concurrent calls
Evgeny Anvaer, Vladimir Dudchenko
SoftBCom, Ltd. (www.softbcom.ru)
22.8.2014

2. IP PBX Asterisk ®: a load test
for smallest corporate level installation
• This is the last test in the planned in advance series of
experiments for determining some reference marks on the
Asterisk’ scalability map
• IP PBX Asterisk is an outstanding open source solution having
all the parameters and credentials for using in corporate level
systems
• The wide implementation area of Asterisk should be
supported by scalability metrics
• Loway Wombat Dialer helps in load testing: it is integrated
with Asterisk and easily can create necessary number of
concurrent calls, playing recorded voice and music

3. HP Microserver Gen8 as a platform
for Asterisk installation
•2-core CPU Intel®
Pentium® G2020T
(2.5GHz/2-
core/3MB/35W),
•2GB RAM installed
•Integrated RAID-
controller B120i,
•2x1TB mirrored disks
installed
•CentOS 6.5 supporting
RAID on B120i controller
•Asterisk 11.11.0 included
into FreePBX 2.11.0.37

4. The Asterisk load test scheme
• It is the same as in the
previous tests of the series
•Wombat Dialer generates
calls
• All the components are in
100Mb LAN
• The load handled by tested
server includes media
delivered by RTP
• The calls directed from the
separate Asterisk server to
the tested server
• Tested server plays back
music and records the calls

5. Some selected results
*100% corresponds to one core, 200% - to 2 cores
Number of
concurrent calls
Peak CPU load* Peak RAM load Hearing quality
101 28,9% 2,9% Excellent
287 65,2% 5,2% Excellent
487 103,1% 7,8% Excellent
687 136,0% 10,3% Excellent
886 169,7% 12,8% Excellent
986 184% 14,1% Excellent
1086 195,6% 15,4% Excellent
1186 200,0% n/a Big distortions:
sound delay for 7-8
sec., vibrations

6. The CPU load to # of concurrent calls
in graph presentation
0,0%
50,0%
100,0%
150,0%
200,0%
250,0%
0 200 400 600 800 1000 1200 1400
CPULoad
Concurrent calls number

7. The concise conclusions
• Asterisk running on HP Microserver Gen8 having two-core CPU
and 2GB RAM can serve more than 1000 concurrent calls
• HP Microserver Gen8 could be used as a low-budget corporate
level platform for IP PBX Asterisk characterized by heightened
reliability (mirrored disks and built in power supply) and rather
high performance (two core CPU)
• In normal office load conditions (without call-centers functioning
on these resources) it could be implemented for somewhat up
to 2000 extension numbers
• The tested configuration could serve mid-size call-centers, but
accurate sizing needs examining detailed load model, and taking
into consideration resources necessary for monitoring, analytics
and corporate applications integration means

8. Final considerations
• All the load emulation details, possible errors, load character
and limitations are discussed in the previous test observation
concerning quad-core CPU Intel Xeon E5506:
http://softbcom.ru/articles/load-test-of-ip-pbx-asterisk.php
• We recommend to implement CPU load monitoring for all the
cases when planned Asterisk load may reach 50% of estimated
maximum with generating alerts of overcoming the delimited
threshold
The Loway Wombat Dialer was kindly presented for
the test by Swiss company Loway. Designed for
telecasting, it fits 100% to the test demands. Its easy
use and power made this test possible