prngd[2272]: Could not fork: Not enough space in hp-ux

[Shehan]

Hi Stevan

Understand the situation about the keeping the swap in external storage. If external storage is down, system may be stuck due to low swap space.

Anyway I will try to get rid of the utilized space from the local disk and try to keep the 12GB swap space in the local disk.BTW, we are unable to reinstall the system as the systems is being used since 2004.

Also, I would like to know the steps in order to create 12GB swap space in the VG00.Please assist me on that.

Regards
Nirukshitha

[Steven E. Protter]

Yes, I meant to say NON-local.

Thanks. No points for this.

[Shehan]

Hi Dear friend

Glad to say that there is a high possibility of getting additional space from the local disk(VG00) by deleting unwanted space.So please let me know most suitable method for increasing swap?Either external storage or internal . Also, as Duncan said this systems is having two redundancy paths and mutipath is being configured with XP24000 external storage. Please assist me.

Regards
Nirukshitha

[James R. Ferguson]

Hi:

I'm not going to comment on the local vs. SAN discussion. Duncan has already made the points I would.

You don't need to add your secondary swap device on vg00 if you don't have room there; put it anywhere you can.

To add a 12GB secondary swap, do:

# lvcreate -C y -r n -L 12000 -n lvolN /dev/vgXX

# swapon -p 0 /dev/vgXX/lvolN

# echo "/dev/vgXX/lvolN ... swap pri=0 0 0" >> /etc/fstab

...obviously, change the 'XX' and 'N' to meet your specific volume group and logical volume values.

Regards!

...JRF...

[Shehan]

Hi Jeames

If we create the swap in the same VG00, can we use same steps in order to create secondary swap?

Also , as I know " swapon -p 0 /dev/vgXX/lvolN" setting the priority of the swap. If we use "0", will this be a secondary swap? or first piority?


Regards
Nirukshitha

[James R. Ferguson]

Hi (again):

By definition, primary swap is the device file swap in 'lvol2' of vg00. The swap priority has nothing to do with primary versus secondary as the definitions are used. You can have _multipe_ "secondary" swap devices but only one "primary".

The priority of primary swap is one (1). You can set secondary swap priorities to the same or a different value. Using the same would mean any swap activity is interleaved between the devices of equal priority. This is potentially benefical but potentially detrimental both in terms of disk head movement.

In the end analysis, you do NOT want to actually swap. You need the space for reservation. That is, whenever a process is created (unless there is a deferred swap reservation for the process), swap space is accounted for by the kernel. This is called a reservation. That is, the actual space is *available* or reserved should the process actually need to be paged.

Remember too that you must activate any secondary swap during startup. This is the reason for including entries for secondary swap devices in '/etc/fstab'. See the 'swapon(1M)' manpages for more information.

Regards!

...JRF...

[Shehan]

Hi

What's the reason for utilizing swap space ?


Regards

Nirukshitha

[Duncan Edmonstone]

Nirukshitha,

You need to know the difference between *using* swap space and just *reserving* swap space.

I'm sure you know that HP-UX, like most modern OSs is a "Virtual Memory" system - that is the processes in it can map to more memory than you have physically installed in the system.

Swap space is there for when the system comes under real memory pressure. In this situation rarely accessed pages of real memory are "paged out" onto the swap partition to free up memory for pages that are more regulalry accessed. In more severe situations, the memory of an entire process that hasn't been on the run queue in a while will be swapped out to the swap partition.

Read more here:

http://docs.hp.com/en/B2355-90672/ch06s02.html

To be sure that it is always in a position to do this "paging out" or "swapping out", HP-UX reserves swap space when a process allocates memory. This swap space won't actually get used (written to), unless paging/swapping actually occurs.

I think in your case you were simply reserving swap rather than using it. You can check whether you have started paging out, by running:

vmstat 2 10

and looking at the po column. SIgnificant numbers here means you are paging out, and should either reconfigure Oracle to use less memory, or install more memory in your system (and of course increase swap space when you do).

HTH

Duncan

[Shehan]

Hi

My local disks are mirrored.So , Do I need to mirror newly created secondary swap's ?

If so , let me know the command in order to mirror this swap logical volume.anyway I am going to follow below steps to create secondary swap.


# lvcreate -C y -r n -L 12000 -n lvol11 /dev/vg00

# swapon -p 2 /dev/vg00/lvol11

# echo "/dev/vg00/lvol11 ... swap pri=2 0 0" >> /etc/fstab

Please correct if I am wrong.

Regards
Nirkshitha

[Avinash20]

Yes, this is correct..