topic Re: Optimazing memory usage in Hp-ux itanium in Operating System - HP-UX

Optimazing memory usage in Hp-ux itanium

likid0 — Wed, 22 Nov 2006 07:31:46 GMT

Hy people:

I have a sever using 11.23 ia64, and i was wondering if it was posible to reduce the memory the kernel uses when it boots the machine, at the moment i have:

Physical memory = 1031432 3.9g 100%
Free memory = 23548 92.0m 2%
User processes = 582096 2.2g 56% details with -user
System = 415088 1.6g 40%
Kernel = 327533 1.2g 32% kernel text and data
Dynamic Arenas = 115942 452.9m 11% details with -arena
vx_global_pool = 24684 96.4m 2%
spinlock = 14101 55.1m 1%
vx_inode_cache = 11691 45.7m 1%
VFD_BT_NODE = 11000 43.0m 1%
vx_buffer_cache = 5248 20.5m 1%
Other arenas = 49218 192.3m 5% details with -arena
Super page pool = 83909 327.8m 8% details with -kas
Static Tables = 94277 368.3m 9% details with -static
nbuf = 46720 182.5m 5% bufcache headers
pfdat = 24179 94.4m 2%
vhpt = 8192 32.0m 1%
text = 6993 27.3m 1% vmunix text section
bufhash = 2048 8.0m 0% bufcache hash headers
Other tables = 6143 24.0m 1% details with -static
Buffer cache = 87555 342.0m 8% details with -bufcache
UFC file mrg = 0 0.0b 0%
UFC meta mrg = 0 0.0b 0%

and i want to reduce the system memory, i have alredy changed the dbc to 10, and i dont know if i can change any more kernel parameters to reduce the amount of memory the system uses, without afecting its performance?.

cant i reduce the nbuf or something similar?

thnx a lot

Re: Optimazing memory usage in Hp-ux itanium

Steven E. Protter — Wed, 22 Nov 2006 07:38:11 GMT

Shalom,

100% memory use is not a problem. What that really means is you aren't wasting any.

http://www.hpux.ws/system.perf.sh
These scripts are believed to run correctly on 11i v2 Itanium.

http://www1.itrc.hp.com/service/cki/search.do?searchString=UPERFKBAN00000726&docType=Security&docType=Patch&docType=EngineerNotes&docType=BugReports&docType=Hardware&docType=ReferenceMaterials&docType=ThirdParty&hpweb_printable=true&searchCrit=allwords&search.x=28&admit=-682735245+1164199009340+28353475&mode=id&category=c0&search.y=8

That link is the ultimate guide for beginners to HP-UX performance and is very relavent to HP-UX running on Itanium.

SEP

Re: Optimazing memory usage in Hp-ux itanium

likid0 — Wed, 22 Nov 2006 08:06:20 GMT

Thnx m8, i am goin to have a look at both of them now, but the problem i have in this server i forgot to write it is:

it has a instance of a database runing, when they try to start the second one it saysit doesnt have enough memory, and they asked me if
i could try and reduce the s.o usage of memory until the physical memory they have bought gets installed in the server

thnx again

Re: Optimazing memory usage in Hp-ux itanium

likid0 — Wed, 22 Nov 2006 08:13:56 GMT

hy steve,

I cant get to the second link u sent, i am a europe user, and when i log in from europe it says its no available.

Re: Optimazing memory usage in Hp-ux itanium

Bill Hassell — Wed, 22 Nov 2006 09:35:52 GMT

If you have a lot of swap space, then your problem has nothing to do with memory usage. HP-UX is a virtual memory system so you can run a lot more processes than will fit in RAM. The most likely reason for failing to start another database is that the database is only a 32bit application and probably uses shared memory. Because 32bit programs are so limited, it is difficult to get large amounts of shared memory (there is only one default map for all shared memory objects). You can try reducing the size of shared memory in your two databases and see if they start working.

However, your database performance can slow down a lot without enough shared memory so you may wish to consider memory windows or the new MPAS executable model. Memory windows do not require rebuilding the database executables while MPAS will require this. Do you have a 32bit database application?

Re: Optimazing memory usage in Hp-ux itanium

Bill Hassell — Wed, 22 Nov 2006 09:56:13 GMT

I just found this very detailed paper about 32bit programs on 11.23 and the Adaptive Address Space (AAS) features:

http://docs.hp.com/en/8681/aas_white_paper.pdf

Re: Optimazing memory usage in Hp-ux itanium

Hein van den Heuvel — Wed, 22 Nov 2006 11:12:12 GMT

Bill, Good reference paper!

Daniel,

What is the system 'doing'.
Database application? File server?
How many user processes (tens, hundreds or thousands?)
Lots of shared sections in use? (ipcs -m)

Be sure to read up a couple of prior discussion in this area. For example:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=951641
and
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=954245 (IA64)

I'm sure you already carefully studied the "performance Cookbook":
http://h21007.www2.hp.com/dspp/files/unprotected/devresource/Docs/TechPapers/UXPerfCookBook.pdf

http://docs.hp.com/hpux/onlinedocs/B3929-90011/B3929-90011.html

Here is an other interesting read:

http://bbobb.itpub.net/post/69/53180
(Japanese context, English text :-)

Cheers,
Hein.