Here is a quick-and-dirty first estimation of a possible memory shortage:
Issue "svmon -G" and compare the numbers marked bold in the following example:
Code:
size inuse free pin virtual
memory 1572864 1557689 15175 389150 1311648
pg space 2097152 427109
work pers clnt
pin 388839 0 311
in use 977383 0 580306
PageSize PoolSize inuse pgsp pin virtual
s 4 KB - 1448041 427109 318814 1202000
m 64 KB - 6853 0 4396 6853
The memory is measured in 4k-pages here. The ~1.5 millions means 6GB real memory therefore. Then compare the "inuse" number with the "virtual" number and if the "virtual" number is significantly higher the difference is about the memory you are lacking. i.e 1.5 mio "inuse" versus 2 mio "virtual" means you need to add about 500k x 4k ~= 2GB memory.
Again, this is only a QUICK and ROUGH estimation, not an in-depth analysis. Such an analysis might well reveal a different number.
Another place to look is "vmstat -v", especially for machines with a high I/O-workload. Have a look at the lines marked bold in the following example:
Code:
1572864 memory pages
1487316 lruable pages
15273 free pages
1 memory pools
389150 pinned pages
80.0 maxpin percentage
20.0 minperm percentage
80.0 maxperm percentage
37.0 numperm percentage
551288 file pages
0.0 compressed percentage
0 compressed pages
37.0 numclient percentage
80.0 maxclient percentage
551288 client pages
0 remote pageouts scheduled
17676 pending disk I/Os blocked with no pbuf
151067 paging space I/Os blocked with no psbuf
2484 filesystem I/Os blocked with no fsbuf
0 client filesystem I/Os blocked with no fsbuf
474712 external pager filesystem I/Os blocked with no fsbuf
0 Virtualized Partition Memory Page Faults
0.00 Time resolving virtualized partition memory page faults
These are totals therefore repeat that command every minute or so and observe the change in these numbers. If they grow at a very fast rate the system has not enough memory to spare for buffered disk-I/O. Probably you will notice a very bad filesystem performance because of this. Usually this is due to a very constrained memory situation and while you might somewhat deescalate the situation by some tuning you will probably need more memory to solve tis problem.
I hope this helps.
bakunin
