Ubuntu 10.10 not using swap

I have never found my swap space being used. Is it normal? If not, how can I trace the problem and fix it?

Thanks

 

Hi aigle:

I have installed Ubuntu on some fairly low-end computers (including my current laptop), and it never uses swap. I just assumed it was Ubuntu being lean and mean as compared to windows, and my complete lack of memory intensive computing. I always lower the swappiness value to 10 but, as an experiment, I guess you could increase it from the default of 60 and see what happens.

 

I don't have it because of my netboook's limited hard drive space. Faster not using virtual memory anyhow.

 

swap is mostly used when your ram reaches more then peak value of its original if you have enough ram then your swap hardly used

The default value is 60-70 mostly

http://www.linuxtopia.org/online_bo...nt/rhel_6_resource_management_sec-memory.html

 

Not always faster , some use-cases it can be more performant/efficient to page out dormant but used address space from memory to swap and free the space for buffers and cache.

http://lwn.net/Articles/100978/ benchmarks show that I/O can suffer by 50% .

For general desktop use, most distros have a sane default. Average desktop use does not stress the system enough for the swapiness to be a significant factor in performance.

Cheers, Nick

 

You might be 'rewarded' with seeing something swapped when you rip a DVD movie to mp4.

 

Or mkv to DVD structure...not that I'm breaking any laws. .

Later...

 

While probably not relevant in your case, it might be useful to know that instead of a swap partition you can also use a swap file (similar to Windows) which can be created anywhere (e.g. on a second harddisk).

 

It looks to me like you have no swap set up - 0 bytes of 0 bytes.

 

After looking again at aigle's picture it's obvious that you're absolutely right.

No swap -> no swap usage

 

It,s very starnge. What about this swap partition?

Thanks for all the people who replied.

 

Is it in your fstab ?

Cheers, Nick

 

My netbook has a SSD not hard drive.

Just got swapd. How should I configure it for my 8 GB SD card? I use it for my download directory as well.

 

ok, it,s like this. i can,t understand it fully by the way.

 

I'm using swapd, because it should save more space. Do you have settings for that?

 

hmm.. wat is swapd?

 

Aigle, try swapon -a
and check with free

 

It is in the main repository. Google "swapd".

 

About swap faq's and making a swap file. Scroll to Four-step Process to Add Swap File.

Four-step Process to Add Swap File

I don't know whether swapd is the preferred solution.

 

I've never used swapd. But according to the manpage you should use the swapdir option in your swapd.conf file.

 

It's traditional to use swap partitions 100%-200% of total memory. Swap partitions are much faster than swapd, which needs to create swap files on the fly. Consider using swapd with a minimal swap partition.

 

@tlu: I found a good guide here: http://ubuntuforums.org/showpost.php?p=3598334&postcount=6
Already changed swapdir.

@rudyl: I've used 200% total (8 files from 3 GB). Swap partitions are faster when creating swapd files, but they should be around the same in the 2.6 kernel.

 

Yes, I see. Thanks. Old habits I'll have to try some swapd.

 

i get this

 

can swapd be used on a system that is hibernated? I read some documentation on ubuntu that the swap partition needs to be at least the same size as the ram installed for hibernation that's why I have a 3gig swap partition on a laptop.