User looks at AMC, AMC is showing a higher used Memory for his namespace by 3 Gb or so.
Check if they are using Secondary Index, since Secondary Index is stored only in RAM. Since secondary index are stored in RAM only. There are multiple ways of checking for secondary index. You can run the following on the logs to Grep for it.
tail -1000 /var/log/aerospike/aerospike.log | grep “namespace”
Oct 09 2014 17:43:39 GMT: INFO (info): (thr_info.c::4545) namespace ns1: disk inuse: 13891448832 memory inuse: 1157620736 (bytes) sindex memory inuse: 2777420045 (bytes) avail pct 95 cache-read pct 0.00 memory inuse: 1157620736 (bytes) (1.157 Gb) sindex memory inuse: 2777420045 (bytes) (2.777 Gb) ========================================================== TOTAL: 3935040781 bytes = 3.935 (Gb)
Also even on AMC, it shows them how to look up windex memory inuse also. More info can be found here for AMC on sindex