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Re: Recommended pagefile/swapfile size for IA64 with v8.3

 
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Volker Halle
Honored Contributor

Re: Recommended pagefile/swapfile size for IA64 with v8.3

Dmitry,

for the INVEXCEPTN crashes at SMP$RESTOREL, it would be useful to also get the following information:

SDA> SHOW CALL/SUMM

as the CLUE CALL and CLUE STACK commands have not been implemented for OpenVMS I64 and this data therefore is not in the CLUE file.

The spinlock handling code itself (execlet SYSTEM_SYNCHRONIZATION_MIN) has not been patched for V8.3-1H1, but the problem may be in the caller's code.

If you have an OpenVMS support contract with HP, I would strongly suggest to escalate these problems (after patching the system to the current patch level - as Hoff has suggested). Consider to collect at least one crashdump of each type for escalation.

Volker.

Re: Recommended pagefile/swapfile size for IA64 with v8.3


For those how are interested in or might be curious: the issue has a continuation and a resolution.

To summarize, the server
- is running under OpenVMS 8.3-1H1, carries 4Gb RAM on board and has rx4640 architecture
- was not working stably under the high load of a special application (single master application that was handling nearly 50 similar images; each image has ~50Mb size and can be launched several times)
- server's crash occurred only if this application was working. I wrote a simple application that allocates memory on demand and doesn't release it. Server survived even when this program consumed 4Gbs of physical memory and nearly all free space (7Gb + 8Gb) of two page files. Once this Master App is launched (even with 1 image loaded) - server crashed. This is where I started to suspect this Master App of being guilty in crashes.
- one strange thing about all this stuff was that crash occurred only at the very edge when physical memory is about to be totally consumed and page file needs to be involved... Also I never observed that page file is used when Master App is running. And it was always used when I ran my 'memory leak' program...

Not so long ago we got some new RAM and decided to replace the old one to see if this can be some kind of hardware issue with the memory. All eight 512Mb banks were replaced. I started the 'memory leak' program and launched Master App. Another crash occurred in exactly the same way as before (once 4Gbytes of new physical memory were over).
Then we decided to mix old memory with the new one - for the server to run with 8Gb on board. This was the point where issue disappeared. Both page files are now fully involved. Server is operating stably even if almost all physical memory (8Gbs) is consumed right before I start the Master App. I was not able to initiate a crash even when system was running low on both Physical Mem and two 7&8 Gb page files...

I have an assumption that this system was installed on a 8Gb server and then it was downgraded to 4Gb but some system settings were not tuned to this value. But probably I'm wrong. Anyway, the system is up & running and issue is eliminated. Thanks to everyone for assistance, I appreciate this.
John Gillings
Honored Contributor

Re: Recommended pagefile/swapfile size for IA64 with v8.3

Dmitry,

If your system crashed, there should be a dump file. Show that to HP or, even better, someone like Volker, and they will probably be able to tell you exactly why the system crashed.

Crashes aren't solved using voodoo mechanisms like shuffling RAM between slots, unless the dump tells you that is the cause.
A crucible of informative mistakes

Re: Recommended pagefile/swapfile size for IA64 with v8.3

John,

As you can see from the thread above I was providing all requested info to you and Volker and other guys.

In my previous post I just wanted to describe how the issue appeared and behaved and how it was eliminated in the end - probably this will help someone else...

Some questions are still unclear (like 'why pagefiles were not involved with 4Gbs onboard and why did they start working with 8Gbs on board') but I'm not sure if crash dumps or crashes themselves have something to do with it... But if you wish - I can still capture any info.

Best regards,
Dmitry Sinelnikov
abrsvc
Respected Contributor

Re: Recommended pagefile/swapfile size for IA64 with v8.3

This may not be particularly relevant, but I find it interesting that the problems occur with physical memory capped at the 32bit addressing boundary...