[DOUBT] Memory high in idle process on Solaris 10 (Memory Utilization > 90%)

UNIX Solaris
1

Hi Experts,

Our servers running Solaris 10 with SAP Application. The memory utilization always >90%, but the process on SAP is too less even nothing.

Why memory utilization on solaris always looks high?

I have statement about memory on solaris, is this true:
Memory in solaris is used for I/O cache, so if there is no memory in used, memory will be used by I/O cache. If the Application need memory, the I/O cache will release the memory. If the "sr" value on vmstat > 300, there is bottleneck on memory.

What is the mechanism of memory utilization on solaris?

Any comments are welcome.

Thanks
Edy

2

To check amount of memory used by applications (Anon pages) and file cache (Page cache pages) on Solaris, run:

echo "::memstat" | mdb -k

You can post the output here if you are not sure how to interpret it.

3

Look here, it is a Dtrace script which will allow you tu examine allocation of your memory

http://www.brendangregg.com/DTrace/rwtop

4

From the script description:

# This is measuring reads and writes at the application level. This matches 
# read and write system calls.

Don't see anything about memory utilization there.

5

What does that means ?

You should post some factual figures like prstat -Z and the already mentioned mdb output to help figuring out how your memory is used.

This correct. However, note that this cache memory is reported as free memory if you are using UFS. ZFS cache is reported as used memory though.

There is no precise threshold. As long as the "sr" value stays at zero, you can be sure there is no pressure on RAM.