Error Creating Shared Memory

[dnepr]

On an S85 box with 8GB of memory, when we try to start Sybase, we get the following errors:

00:00000:00000:2002/05/08 10:37:17.74 kernel os_create_region: can't allocate 254234624 bytes
00:00000:00000:2002/05/08 10:37:17.74 kernel kbcreate: couldn't create kernel region.
00:00000:00000:2002/05/08 10:37:17.74 kernel kistartup: could not create shared memory

Can someone point me in the right direction to resolve this? Is it a paging problem? Problem with VMM? What?

Thanks

 

[gheist]

problem with shared memory base address (or size) in your Sybase, not OS, there is no /kernel file in AIX

 

[AIXSPadmin]

Sybase is reaching the maximum size of shared memory a process can allocate which will create the errors you are seeing.

 

[gheist]

As you are most likely running freebsd - try recompiling your kernel with
option SHMMAXPGS=(expected_shared_memory/page_size(4096 on x86) )*1.5
Informix/Linux works well in emulator

No system can allocate too much resident & shared memory (50% ram is some logical maximum?)

 

[avadh]

Hello,
vi /etc/security/limits change data,stack,rss to -1.

make vmtune changes.

 

[gheist]

nope - SHM is out of these limits

 

[AIXSPadmin]

Forgive the text-wrap, however, below is the ipc limits for AIX v3.X-4.3.2 and up I believe the 4.3.2 limits also exist for v5.1.

AIX VERSIONS 3.2.5 - 4.2.0 4.2.1 4.3.0 4.3.1 4.3.2
------------- ------- ------ ------ ------
Semaphores:

Maximum number of semaphore IDs 4096 4096 4096 4096 131072
Maximum semaphores per semaphore ID 65535 65535 65535 65535 65535
Maximum operations per semop call 1024 1024 1024 1024 1024
Maximum undo entries per process 1024 1024 1024 1024 1024
Size in bytes of undo structure 8208 8208 8208 8208 8208
Semaphore maximum value 32767 32767 32767 32767 32767
Adjust on exit maximum value 16384 16384 16384 16384 16384

Message Queues:

Maximum message size 65535 4MB 4MB 4MB 4MB
Maximum bytes on queue 65535 4MB 4MB 4MB 4MB
Maximum number of message queue IDs 4096 4096 4096 4096 131072
Maximum messages per queue ID 8192 524288 524288 524288 524288

Shared Memory:

Maximum segment size 256MB 256MB 256MB 2GB 2GB
Minimum segment size 1 1 1 1 1
Maximum number of shared memory IDs. 4096 4096 4096 4096 131072
Maximum number of segments per process 10 11* 11* 11* 11*

 

[avadh]

Hello,
check /etc/security/limits and change them to -1 then try sybase and see what the results his.

 

[bjverzal]

Dont forget to put EXTSHM=ON in /etc/environment. This will allow for more than 11 SHM segments. This may be an issue here.

Bill.

 

[avadh]

Hello,
if the user wants this problem fixed or wants to get sybase working then needs to check /etc/security/limits file and see what the data,stack and RSS is set at.
If they are not set to -1 then it has to be setup. EXTSHM does not have to be done on AIX side.

AIX does not care. If you set limits to -1 it will give what ever memory application needs. AIX does not care how much memory you take. The problem may be with sybase. AIX does not enforce any soft or hard limits. It is the application that does.

What level AIX is running on S85 and what level of sybase.