topic Re: how to extend the swap file system in Operating System - HP-UX

how to extend the swap file system

rajesh73 — Tue, 22 Mar 2011 04:35:13 GMT

i want to extend swap sapce 4 GB to 10GB.kindly advice how to extend .

$swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4096 74 4022 2% 0 - 1 /dev/vg00/lvol2
reserve - 1683 -1683
memory 3060 2152 908 70%
total 7156 3909 3247 55% - 0 -

Re: how to extend the swap file system

Torsten. — Tue, 22 Mar 2011 04:41:25 GMT

Consider to create another LVOL for swap.
SAM will help you.

Re: how to extend the swap file system

rajesh73 — Tue, 22 Mar 2011 04:49:45 GMT

"Consider to create another LVOL " means to create new lv or extend the lv

kindly find the below preocedure
1.go SAM
2.disk file system
3.swap
4.in actions menu-two options is availble which option i want to chose
add device swap-
add file system swap--

5.their is reboot required for after file system creation

Re: how to extend the swap file system

Torsten. — Tue, 22 Mar 2011 04:53:01 GMT

Create a new LVOL, extending is not possible.

Re: how to extend the swap file system

P Arumugavel — Tue, 22 Mar 2011 05:24:47 GMT

Extending primary swap is not possible. But in some way you could try which is not reliable.
Either going by creating secondary swap through sam/CLI, or change the swap value while re-ignite your system.

Regds...

Re: how to extend the swap file system

Torsten. — Tue, 22 Mar 2011 05:28:49 GMT

But the question is if you really need such large swap space?

Re: how to extend the swap file system

rajesh73 — Tue, 22 Mar 2011 06:10:10 GMT

yes ,we need total swap space is 10GB

Re: how to extend the swap file system

P Arumugavel — Tue, 22 Mar 2011 06:20:13 GMT

Please read:

The amount of swap, added to the amount of memory available, defines the virtual memory available for processes. The minimum recommendation is twice as much swap space as physical memory. Keep in mind, this is an "old" formula. If you have two, three, four or many more gigabytes of physical memory, this would result in way too much swap space. Granted, there are the pathological cases that would require you to have eight to ten gigabytes of swap with, say, four gigabytes of physical memory. If you try to execute a process that would exceed the amount of available memory plus available swap, you will get a "out of memory" message. If you configure more swap than you will ever need, you are wasting disk space. The correct swap size will vary considerably depending on the size and number of application(s) run on a system. The correct swap size can be determined by monitoring swap usage while working with real data. This could be done either with the swapinfo command or using a tool like HP's Glance Plus. Glance Plus allows you to monitor system resources on a per process basis and will display the high water mark (since you started glance). You would configure a system with more swap space than you expect to need, then run Glance Plus while running an application(s). By monitoring the high water mark, you can determine the maximum swap space used and adjust the swap size accordingly. Obviously, if you experience out of memory errors, swap size is too small.

There are many systems with less swap space than physical memory. This is perfectly fine. The person who specified the system probably recommended all that memory so that they would not have to swap! We have seen systems with swap space equal to 50% that of physical memory. Just be sure to have swapmem_on EQUAL TO 1!!

NOTE: For best performance, swap space should be distributed evenly across all disks configured with swap, at the same priority .

Rgds...

Re: how to extend the swap file system

Torsten. — Tue, 22 Mar 2011 06:50:28 GMT

I hope this is not based on the old and obsolete formula

swap = 2.5 x RAM size.

However, create a new device swap inside a new LVOL.

Re: how to extend the swap file system

Dennis Handly — Fri, 25 Mar 2011 23:25:47 GMT

>we need total swap space is 10GB

You plan to run applications that need 6 Gb + 3.2 Gb more than you are using when you did that swapinfo?

Re: how to extend the swap file system

Ismail Azad — Sat, 26 Mar 2011 09:27:27 GMT

Hi,

> Extending primary swap is not possible. But in some way you could try which is not reliable.

Well... This can be done with Ignite or booting into lvm maintenance mode.

Regards
Ismail Azad