when will I hit the 32 bit limit?

[Dave Chamberlin]

Hello,

I am running Oracle database and apps (32 bit) on an N-class, hpux 11.0, w 5.5G RAM. I have no memory issues at this time, but will need to add another oracle database soon on this box. I have read about a 1.75GB limit of shared memory for 32 bit apps and dont quite understand which processes are subject to the limit. On an average day, the RAM util is about 4.8GB, almost all is used by oracle generated processes. The oracle SGA uses 1.46GB (shared pool+block buffers). How can I tell when I will be at the 32 bit limit? What are my best options when I get to the limit?
Thanks

[RAC_1]

Yes, as you understand there is a limit of 1.75GB. But that with enabling share_magic on the pplications. You must read /usr/share/doc/proc_mgmt and mem_mgt closely.

Anil

[A. Clay Stephenson]

There is a way to have your cake and eat it too -- Memory Windows. 32-bit processes are limited to 1.75GB of shared memory and that is where you are going to have problems because the total of all the shared memory in 32-bit land cannot exceed this value. However, by using memory windows in 32-bit land, each group of related processes gets its own shared memory windows so that Oracle Instane "A" can be limited to 1.75GB and Oracle Instance "B" gets its own 1.75 GB chunk as well.

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B3782-90807/B3782-90807_top.html&con=/hpux/onlinedocs/B3782-90807/00/00/26-con.html&toc=/hpux/onlinedocs/B3782-90807/00/00/26-toc.html&searchterms=Windows%7cMemory&queryid=20040628-104343

Of course, the better answer is to migrate everything to 64-bit land and forget all this nonsense.

[Dave Chamberlin]

Thanks for the info on windows. The question I still have is how much of the RAM I am using is "shared" at this time? Also - on the mem windows, it it as easy as rebuilding the kernel with max_mem_window set to > 0 to implement - or are things going to break on the system? What must be done afterwards?
thanks

[RAC_1]

The kernel parameter shmmax is the shared memeory you have set on your machine.

Get a tool shminfo to which is what and how..

Anil

[Dave Chamberlin]

shmmax on my machine is 1073741824 (1.07GB). Running ipcs -ma shows one oracle process using this size. There is also another oracle process with segsz about 500M. Do I have to add up everything in the segsz column to get the total shared memory as it applies to the limit? If that is the case I am at 1.71G now and can only use another 90M. This was the output of the ipcs -ma command (SEGSZ is on the left):

IPC status from /dev/kmem as of Mon Jun 28 11:37:06 2004
T ID KEY MODE OWNER GROUP CREATOR CGROUP NATTCH SEGSZ CPID LPID ATIME DTIME CTIME
Shared Memory:
m 0 0x411c0231 --rw-rw-rw- root root root root 0 348 519 519 18:24:47 18:24:47 18:24:40
m 1 0x4e0c0002 --rw-rw-rw- root root root root 2 31040 519 521 15:34:36 18:24:47 18:24:40
m 2 0x41200cec --rw-rw-rw- root root root root 2 8192 519 521 15:34:36 18:24:40 18:24:40
m 2563 0x331818a9 --rw------- root root root root 3 1129512 1346 10084 7:45:08 18:25:30 18:25:27
m 4 0x6d181758 --rw-rw-rw- root root root root 2 47120 1346 10084 7:45:08 no-entry 18:25:27
m 90117 0x0c6629c9 --rw-r----- root adm root adm 2 12917044 26281 29148 9:30:55 no-entry 8:33:54
m 6 0x06347849 --rw-rw-rw- root adm root adm 0 77384 1974 26281 8:33:54 8:33:54 18:27:16
m 519 0xffffffff --rw-r--rw- root adm root adm 0 22908 1969 1969 18:27:17 18:27:17 18:27:17
m 33800 0x00000000 --rw-r----- oracle8 dba oracle8 dba 547 1073741824 9825 18875 11:36:59 11:36:55 4:03:03
m 12297 0x77bde5c4 --rw-r----- oracle8 dba oracle8 dba 547 497016832 9825 18875 11:36:59 11:36:59 4:03:03
m 17418 0xa86e2b08 --rw-r----- oracle8 dba oracle8 dba 6 131379200 8378 13176 15:45:42 16:31:14 16:39:01

thanks