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100% Memory Usage

 
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Frequent Advisor

100% Memory Usage

Hi all,

I have a V-Class with 5GB RAM, with a small 2GB disk swap volume. After a reboot, glance shows me at 100% memory usage, and 90% swap usage, running a Progress database. This is something new within the past few days. I am stumped as to the problem. The only thing I can think of is that maybe the swapmem_on parameter. Any thoughts?
12 REPLIES 12
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Honored Contributor

Re: 100% Memory Usage

Do a ls -l /stand/vmunix, is it within the last few days????

swapinfo shows what?

dbc_min&max ?? from kmtune

any errors in dmesg or syslog??


live free or die
harry
Live Free or Die
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Honored Contributor

Re: 100% Memory Usage

Hi

Any kernel changes recently ?

Whats your buffer cache set to ?

Regards

Steve
take your time and think things through
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Honored Contributor

Re: 100% Memory Usage

The obvious question first: What has changed in the past few days? Have you done a large data load into the DB? Any large reports running? Large queries?

The swapmem_on parameter will not effect the memory usage as glance sees it. Are you REALLY swapping? What does swapinfo show?

The first thing to do is drill down into glance further and see what processes are running that are eating your memory.
Highlighted
Trusted Contributor

Re: 100% Memory Usage

Who does your data base maintenance?
Have they added some new instances?

This could be normal. How close were you watching it before the reboot?

Rich

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Acclaimed Contributor

Re: 100% Memory Usage

Hi Jason:

First, of course, what's changed? Posting the output of 'swapinfo -tam' would be helpful. Do you see memory pressure with 'vmstat -S'?
If you have 'glance', looking at its memory statistics is helpful, too.

Regards!

...JRF...
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Frequent Advisor

Re: 100% Memory Usage

dbc_min = 15, max = 20
maxswapchunks = 16384
swapinfo: type=dev (1%) type=memory (82%) type=total (89%)

vmstat shows 0 for 'po'
glance shows 99% Mem Util, 89% Swap Util
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Frequent Advisor

Re: 100% Memory Usage

More info - The only change since last week (when everything worked properly) was that HP Apache was installed. The date on vmunix is June 1st, so no problem there. Also, yesturday both Mem Util and Swap Util were at 100% and the system choked itself, and had to be rebooted during production hours. It is quickly approaching 100% again now. It has never done this before.
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Frequent Advisor

Re: 100% Memory Usage

Make sure there haven't been any changes to the Progress Database. The buffer setting on the server is a multiple of the block size of the database.

So if you use -B 1000 and the blocksize of the database is 2048, then the memory consumption is 1000*2048

This could have become a problem due to an incorrect Buffer (-B) or if someone has rebuilt/loaded the database with a larger block size.

Highlighted
Acclaimed Contributor

Re: 100% Memory Usage

Hi Jason:

One adjustment I'd make is to reduce the buffer cache ceiling ('dbc_max_pct') from 20% (which in your configuration translates to about 1GB RAM) to something like 5-8%. I'd set 'dbc_min_pct' to 2% at the same time. You should see a noticable improvement in memory utilization.

Regards!

...JRF...