memory utilization

[Ivan Ferreira]

>>> How can i prove that memory utilisation that is 99.9% have no bad impact on applications running.

Send to them the "Tru64 UNIX - System Configuration and Tuning" manual, available at the HP Tru64 documentation web page, and ask them to read the sections:

1.5.1.1 Using the UBC
4.4.1.3 Modifying the Percentage of Physical Memory the UBC is Using
11.1.3 Tuning the UBC
12â 1 UBC Memory Allocation

If they are unhappy with UBC memory utilization, change the kernel value menthioned before.

[Mohammad Sanaullah]

Dear All once again can any one jsut tell me what free pages means in the above output of vmstat -P does the UBC pages are also taken as free pages as system frees them whenever applications required the...

if Total Physical Memory=8192.00 M=1048576 pages does that means 1 page equal the 0.007815 MB, if that then my free memory that is
free pages = 4816=4816*0.007815 MB=37MB
ubc pages = 668845 means 5227MB
can i assume that total free memory is 5254MB and rest are Memory Utilised????

Please clear my doubt...

All will get good points......

[Mohammad Sanaullah]

One more thing how to get the page size of the sytem.. i think i have page size of 8k as 2222817 pages allocated shows 16.96 GB that comes only if 2222817*8K = 16.96GB.. then above calculations have to be changed in that respect.

please any one can tell how to know the page size?????

[Ivan Ferreira]

From the same manual menthioned in my previous post:

1.6 Memory Resources

The total amount of physical memory is determined by the capacity of the memory boards installed in your system. The virtual memory (vm) subsystem tracks and manages this memory in 8-KB portions called pages, distributing them among the following areas:

- Static wired memory
- Dynamically wired memory
- Physical memory for processes and data caching

[Mohammad Sanaullah]

Thanks for ur reply??? but dear!!!1

As per your statement one page size is of 8k but some where it is also mentioned 4K is that system specific??? if yes then how i will get what paging size my system is using i am having tru64 v5.1. if there is any command or method to know that will solve my problem.....

thank again in advance

[jim owens_1 · Accepted solution]

Tru64 base memory pages are always 8192 bytes.

The term "page" is not exclusive to VM and may refer to something else.

HP-UX uses 4096 byte memory pages as do other platforms so you will see a lot of 4K page discussions.

[Mohammad Sanaullah]

if thats the fact!!! i can handle situation now better with the customer but it will be better if any one can suggest me the commands to know the same????


thanks

[Ivan Ferreira]

From the output of vmstat

vmstat 5
Virtual Memory Statistics: (pagesize = 8192)


See the the header. No doubts there.

[jim owens_1]

Going back to your vmstat, the order of memory availability is:

free pages = 4816... about 39MB ready for immediate use.

inactive pages = 100738... about 825MB not referenced now and reusable after VM cleanup.

ubc pages = 668845... about 5.4GB that will be reallocated as needed. Note that ubc is where applications have their running code and data that lives on disk unless this is something like an oracle database applicattion.