mem 100% how to fix, urgent!

[Gary L]

Hi

our hp-ux rp box hp-ux11i v1, mem 100% cpu:10% swap 50% disk 1% (data from glance).
how to fix it.

thanks

[Steven E. Protter · Accepted solution]

Shalom,

1) 100% memory use is not a problem. If system response time is an issue or other problems exist, then continue, otherwise stop.
2) 50% Swap use may not be a problem either as a process allocates swap at run time in case it needs to be swapped.

vmstat to see if you are paging.

http://www.hpux.ws/system.perf.sh to gather more data.

If you are indeed paging heavily than you have a few choices.

Lower dbc_max_pct to decrease buffer cache and free up some memory.

Add memory to the system.

SEP

[Patrick Wallek]

There are only 2 basic ways to "fix" 100% memory usage.

1) Add more memory

2) Stop processes / applications that are using memory.

Without more information as to what is running, it is difficult to be more exact.

Another thing to check is your dbc_max_pct setting. If it is still set at 50, then it should be set lower. Without knowing the amount of RAM you have it is impossible to make an intelligent recommendation for the setting.

[Hein van den Heuvel]

>> our hp-ux rp box hp-ux11i v1, mem 100% cpu:10% swap 50% disk 1% (data from glance).
how to fix it.

How to fix what? Is it broken?
How can you tell? Why not share that with us.

You should get a bonus for making use of all the memory.
It was bought to be used and not to just sit there all shiny was it?

Specifally a large value of dbc_max will allow the system to use up all 'free' memory for buffer caches. Nothing wrong with that!

Hope this helps some,
Hein van den Heuvel (at gmail dot com)
HvdH Performance Consulting

[Gary L]

Hi Steven

How are you doing? See you again at HP-UX forums. you answered me a liunx question last week about upgrade liunx OS to u8.

I have check /stand/system our past dbc_max_pct is 5, I have modified to 15 by vi, but mem still 100%. I wanna find out which process or program caused this issue, but I could not find out through glance, top, vmstart -S 5 2, sar etc. how to do next step,
thanks

[Gary L]

HI Hein van den and Patrick

thank you very much for your fast reply.
my HP-UX rp2470 box mem is 6GB.

[Patrick Wallek]

Just changing a value in /stand/system does not accomplish anything.

To get the new value to take effect you have to regenerate the kernel and reboot your system.

[Jaime Bolanos Rojas.]

Gary,

You can use this command to see which processes/programs are using most of your memory:

# UNIX95= ps -eo vsz,ruser,pid,args | sort -rn | more


Regards,

Jaime.

[Steven E. Protter]

Hi Gary,

Pay attention to Patrick's second comment.

use kmtune or sam to change teh dbc_max_pct and see if it helps.

I'm trying to do okay, got some issues here, glad I was helpful on the Linux side.

I think you, IF you actually have a problem are going to need to buy memory for your box.

You are welcome.

SEP

[Gary L]

thanks Jaime

Use your command I checked out the process that using most mem.
But I don't wanna fix it. I think you all are right, mem 100% not a big deal, if have other problems or bottleneck exist, maybe need fix it, but this case cpu 10% swap 50% and disk 1%, maybe not right? current mem is back to 88%.
Hein van den, you are funny guy, I will share you later about which hero program used most mem not to sit there sleep.

thanks patrick and steven.

have a great day

[Bill Hassell]

100% memory useage is not a problem for HP-UX. It is a virtual memory system and will allow a *LOT* more processes to start running even when memory is 100% full. It does this by deactivating lower priority processes and paging them out to swap. If you have 6Gb of RAM and 30Gb of swap space, you could run almost 30Gb of programs. Now performance may be awful because all the programs do is get paged in and out of RAM. With Glance, look at the Memory screen and check the page out rates. If they are less than 10, you are fine -- run more processes. If page out is consistently above 50, then you need a lot more RAM, perhaps another 4-6Gb.

[Gary L]

Hi Bill
thank you very much for your detail reply.

[Gary L]

Hi bill
with glance, my rp box current CPU Util 4%, Disk Util 4%, mem is 95%, Swap Util is 87%.
with sam, I found swap /dev/vg00/lvol2 Mbytes is 4096, is it 4.096G? small? or use another command could check the real space size of swap. page in sometime was 102, sometime was 29 58 0 etc.
cumulative is 37407 and high rate is 1639.3 but page out still = 0, both cumulative and high rate, is it normally?
Other info were:
Total VM : 10.6gb Sys Mem : 3.95gb User Mem: 9.75gb Phys Mem: 16.0gb
Active VM: 7.08gb Buf Cache: 1.60gb Free Mem: 718.8mb

thanks!

[Bill Hassell]

You wrote:

> with glance, my rp box current CPU Util 4%, Disk Util 4%, mem is 95%, Swap Util is 87%.

Swap Usage is two values, reserve and used. The RRRRRRRRRR part of the bar is not real swap usage, just reserved. The UUUUU part is the used area and refers to both page-outs as well as memory mapped files. You might want to add an additional swap area for future growth. swapon can enable this while you are running. Add the entry to /etc/fstab to make it permanent.

with sam, I found swap /dev/vg00/lvol2 Mbytes is 4096, is it 4.096G? small? or use another command could check the real space size of swap.

4096 Mb is 4Gb, a bit small for a 16 Gb machine. I would add another 4Gb lvol for secondary swap space.

> page in sometime was 102, sometime was 29 58 0 etc.
cumulative is 37407 and high rate is 1639.3 but page out still = 0, both cumulative and high rate, is it normally?

Ignore page-in completely. It is a measure of *every* program startup. When a program starts, HP-UX will "page-in" the executable program from the filesystem. Hidden in the same metric is page-in from disk but it is not possible to tell the difference.

However, page-out indicates that a process was deactivated and paged-out to the swap area. Since your page-out number is 0, there is no problem, you have plenty of memory.

[Gary L]

Hi Bill,

thank you very much for your excellent and detail explanation

have a great day

thanks
-Gary