Technote (troubleshooting)
Problem(Abstract)
Upon activation of links, Communications Server runs into critical buffer shortages and memory allocation errors.
Symptom
2012-02-16 11:16:14 EST 256-14(0-10) E (PU)
Critical buffer congestion.
2012-02-16 11:17:40 EST 1-1(1-10) P (PU)
Memory allocation error. Size requested = 0x0140.
Cause
Available buffers ( buf_avail = ) was set to 10000, which is too low. Communications Server will set this dynamically at start up but, in this case, the value was over ridden with a snaadmin command and set too low.
Environment
AIX , Linux
Diagnosing the problem
The following display shows buf_use_status of congested and buf_avail of 10000.
query_buffer_availability display returns the following values:
reset_max_values = NO
buf_avail = 10000
buf_total_count = 79
buf_total_bytes = 67040
buf_rsrv_count = 0
buf_rsrv_bytes = 0
buf_res_use_count = 0
buf_res_use_bytes = 0
peak_usage = 10
peak_decay = 0
throttle_status = 30
buf_use_status = CONGESTED
max_buf_total_count = 82
max_buf_total_bytes = 99728
max_buf_rsrv_count = 0
max_buf_rsrv_bytes = 0
max_buf_res_use_count = 0
max_buf_res_use_bytes = 0
max_peak_usage = 0
max_throttle_status = 30
max_buf_use_status = CONGESTED
debug_param = <0000000000000000000000000000000000000000000000000000000000000000
Resolving the problem
A typical value that Communications Server will set is 2147483392. Communications Server will use 25% of available memory allocated at install for the buffer pool, up to 2GB. This value is set by Communications Server when the /etc/sna/snammlmt.exe is run at install. You can set this value yourself with the snaadmin set_buffer_availability,buf_avail=2147483392.
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