Hi,

I have the same result with 4 servers that 9 servers executing ab in the same time. I tested it before until i configured 9 servers client. With 1 server i can get between 12000 - 14500 concurrent connections.

# ab -n 500000 -c 200 http://192.168.1.11/a.txt
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 192.168.1.11 (be patient)
Completed 50000 requests
Completed 100000 requests
Completed 150000 requests
Completed 200000 requests
Completed 250000 requests
Completed 300000 requests
Completed 350000 requests
Completed 400000 requests
Completed 450000 requests
Completed 500000 requests
Finished 500000 requests


Server Software: nginx/0.7.67
Server Hostname: 192.168.1.11
Server Port: 80

Document Path: /a.txt
Document Length: 5 bytes

Concurrency Level: 200
Time taken for tests: 34.309 seconds
Complete requests: 500000
Failed requests: 0
Write errors: 0
Total transferred: 107500000 bytes
HTML transferred: 2500000 bytes
Requests per second: 14573.44 [#/sec] (mean)
Time per request: 13.724 [ms] (mean)
Time per request: 0.069 [ms] (mean, across all concurrent requests)
Transfer rate: 3059.85 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 4 73.8 2 3006
Processing: 0 10 5.2 9 225
Waiting: 0 9 5.2 8 224
Total: 1 14 73.9 11 3021

Percentage of the requests served within a certain time (ms)
50% 11
66% 13
75% 14
80% 15
90% 17
95% 19
98% 21
99% 24
100% 3021 (longest request)


Thanks.