How to rectify Linux server slowness, maybe related to swap usage?

linux273 · 05-21-2012, 11:27 AM

We have a Linux server and an exclusive process run on that server. The process usually takes around 7 hours to complete but on some days we have also noticed that it took up to 10/11 hours.

We generally use vmstat command to see the memory allocations.

On days, it has ran normally, the ‘Swapped’ indicator (o/p of vmstat) showed ‘0’ whereas on days it ran slowly, the ‘Swapped’/Swpd indicator was a good number ( in M megabytes).

I would appreciate if someone can tell me if swapping is anyway related to the slowness here. If yes, then we do the system use swap memory when thousands of megabytes are still free.

How we can rectify the scenario and avoid slowness?
Any other pointers are also welcomed. Thanks in Advance!!!

UndiFineD · 05-21-2012, 01:33 PM

Ofcourse swapping makes any application slow.
the harddisk is many times slower than internal memory.
as you said this is one process.
the fact that it needs to swap, while there is free memory available,
means the code is not optimized to make use of the memory available.

secondly I wonder if splitting the process into several partial problems would help you
as you can pinpoint more easily when / where the problem originates.

colucix · 05-21-2012, 01:46 PM

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