The first thing I look at, for a feeling of how the system has been behaving since boot is vmstat -s michael@x054:[/home/michael]vmstat -s
Further, I prefer the command lsps -s for an accurate view of how much paging space is being used.
My rule of thumb is that paging space percent used should be less than 20%. I start very small (512MB for 9G of memory on my current system) - because I do not want to see paging activity to/from paging space. Everything above what is needed is just being wasted.
And I definitely disagree with multiple paging spaces to "tune" paging space. If you paging space is active - you have an application "condition", generally a configuration issue. If not, add more memory. Tuning paging space was acceptble back when a large system had 128MB-512MB of memory, and less than 4GB disk space. This is today - forget best practice anno 1994 - at least for AIX.
Further, as said above, AIX caches stuff in memory. Generally there are two categories to worry about: file and computational.
Computational is best compared with legacy *nix memory model while file memory is everything else that AIX caches via virtual memory manager. The premise is i/o to/from memory is faster than i/o to/from disk.
So, on an AIX system is quite common to see the total writes (page outs) to be larger than the reads (page ins) - see above - because the data is being written to disk but just stays in memory (cached) and a physical i/o (page in) is not needed when the data is needed later.
Rather than the nmon view, try the topas view
On the right side, under MEMORY, you can see the Computational (Comp) and other/File memory (noncomp) and below that the Paging Space. In the middle is the column Paging.
Depending on how quick I want to see results I set the interval to 5, 15 or 60 seconds (topas -i ##)
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (1 Reply)
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (3 Replies)
Hi,
We have AIX 5.1 machine of RAM 8 GB and paging space is 8GB. we are getting high memory usage of almost 99%.Can anybody please help in this ?
Partial vmstat o/p
kthr memory
----- -----------
r b avm fre
2 1 278727 1143
There is no paging issue.Becoz in... (5 Replies)
how can I find cpu usage memory usage swap usage and
I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times
my final destination is monitor process
logical volume usage above X % and number of Logical voluage above
can I not to... (3 Replies)
Hi,
I have AIX 5.3TL8 two node cluster using HACMP and have 10g database using RAW devices. I am seeing gradual increase in comp% memory everyday and it reaches 100% and evicts the node, we had 4 evictions in 40days.
I am pasting vmstat and vmo output, anyone seen this issue?
... (5 Replies)
Hello,
Am working on small program that used to calculate the memory usage of AIX servers. Am using svmon -G command to get the memory usage. For example, consider the following output.
$ svmon -G
size inuse free pin virtual mmode
memory ... (9 Replies)
Hi, i have 2 identical web servers using AIX. I use nmon analyser to check their performance.
The server A exceeds 20% memory usage for system, 5% for cache and the rest 75% for processes. While, it uses 4% of Paging Space.
The server B exceeds 20% for system, 45% for cache and 35% for processes.... (24 Replies)