Hello to every body

In sar command with "-B" option there is "pgscank/s" field
the man page says it is "Number of pages scanned by the kswapd daemon per second"

My questions is :

1.if we have high number in "pgscank/s" field can we realize that the server has many swap pages in/out ?

2. does "number of pages scanned by the kswapd daemon per second" means "number of swap pages has been sent in and out by kswapd daemon" ?

3.do you know about "pgscand/s", can you explain it more ?

thanks

Hello and welcome to the forum

Just as a suggestion, you might want to change your username using the instructions at the top of the page here, lest your email inbox ends up with a boatload of SPAM in the very near future.

Regards...

Paging is not the same as swapping. Paging activity may increase when simply running a program, to get their code off disk and into memory, or working with memory-mapped files. This doesn't *NECESSARILY* mean that swap is used. pgpin/s and pgpout/s values refer to 'swappiness'.

Major faults per second (majflt/s), is the measure of disk read activity that needs to happen due to swapping. This indicator is not exclusively for swapped pages, but for *any* kind of pages. A constantly high number of major faults would mean that your process execution is interrupted too often to wait for disk I/O to complete reading pages (code, memory-mapped file data or other memory portions previously swapped out to disk).

That's a good indicator if your system may be lacking memory for its current load; major faults are going to be repeatedly produced if pages previously loaded into memory are getting thrown (swapped) out, due to shortage of memory and then re-requested because they are actively worked on by the current processes.

1 members found this post helpful.

Similarly, as 'just a suggestion', you may want to re-visit the LQ Rules. Specifically, these two:

• Do not post if you do not have anything constructive to say in the post.
• When posting in an existing thread, ensure that what you're posting is on-topic and relevant to the thread. If the content of your post will interfere with the current discussion, you should start a new thread.

Please address posters questions if you're going to reply. Also, there is something mentioned about creating multiple user ID's, too, since this is your SECOND:
http://www.linuxquestions.org/questi...um-4175556925/

TB0ne thank you for your replay

Do you think that we can use "vmstat" command output (my mean is "si" and "so" fields) as indicator for swapping ?
If "si" and "so" values increase and is high , Can we say Linux stores and loads many swap pages ?

Thanks

The man pages for vmstat are pretty comprehensive, and swapping is one of the things tracked there, as it is in sar. The better question is what's going on with your server that you're concerned with this?