Memory measuring tricks:
Total Physical Memory:
# prtconf
Kernel Memory:
# sar -k 1 1
Free Memory:
Ignore the first line it's general information.
# vmstat 3 - consider that each memory allocation assumes similar size swap reservation
Two indicators of a RAM shortage are the scan rate and swap device activity.
Scan Rate:
sar -g or vmstat(sr)
Paging:
Vmstat(po)
Swap Device Activity:
iostat -x
vmstat
sar -d
If there are I/O's queued for the swap device, application paging is occurring.
Process Memory Usage:
Ps -ly ,prstat, top
Pmap -x PID
ipcs -mb - shared memory usage
Swap space:
swap -l reports total and free space for each of the swap partitions or files that are available to the system
swap -s reports the total available amount of virtual memory
sar -r
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