Sponsored Content
Operating Systems Solaris Monitoring Paging and Swapping Post 303027366 by jlliagre on Friday 14th of December 2018 09:28:04 AM
Old 12-14-2018
Quote:
Originally Posted by javanoob
Hi Jilliagre
There's an extra "i", my pseudo is jlliagre, not jilliagre...
Quote:
q1) Do you mean if ProcessA has made reservation on the virtual swap (ram & disk), another Process B can actually use this reserved space for actual physical paging into RAM and out to swap/disk ?
Unless shared memory enter in the game, no it can't.
Virtual space allocated by a process is for its exclusive use. Note again that virtual memory is not the same as physical memory. No particular space is reserved, that's just an amount of space. The OS is free to map this virtual space to whatever physical backend it likes.
Quote:
q2) If i still have free memory (ard 10G reported in memstat's free) but have physical swap being used (ard 3G in swap -l), what does this means then ?
That means the OS stored 3G of seldom used virtual memory to disk, improving overall performance.
Quote:
Doing vmstat for 30 minutes, did not see any counters jump for si/so, pi/po, and SR (all 0s) ?
Could i have some kind of spike @ certain timing (using up all the free ram), and cause the physical swap to be use ? < could this be 1 possiblity ?
The si/so counters are unlikely to move under normal circumstances but only during severe RAM shortage.
The pi/po counters move when there pagination occur. Most of that pagination might be unrelated to VM shortage, that might simply be a file being read by some process.
Th sr only move if there is RAM shortage.

A static 3G doesn't cause any activity by itself.

The most important counter to monitor is "sr". As long as it stays equal to 0, there is no RAM shortage.
You might have VM shortage though, and the vmstat column to monitor is then "swap" (available swap space).

Note also that your system might use zones configured with virtual memory capping. In such case you might have swap usage without (global) vm shortage.
This User Gave Thanks to jlliagre For This Post:
 

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

Excessive Paging&Swapping!

Hi all! Working on Oracle v8i/9i on Unix Sun Solaris v8.0. I am experiencing excessive paging & Swapping.Would like to know the cause. I guess:could be due to inappropriate setting of Unix Kernel Parameters... Please correct me if I am wrong! Thanks&Regards, Amit. (5 Replies)
Discussion started by: Amitstora
5 Replies

2. Filesystems, Disks and Memory

Paging and Swapping

Hi Guys: Would like to know how to check system swapping and paging and some theory on how they function. I am an oracle dba and my environment is 8171 on AIX 433. We have a 1GB of RAM on the box and I am educating myself to see how much more SGA can be accommodated on the box and what are the... (2 Replies)
Discussion started by: ST2000
2 Replies

3. UNIX for Dummies Questions & Answers

how to get swapping info

Hi How can I determine if swapping is occuring on a server. Thanks, Leo (2 Replies)
Discussion started by: leo
2 Replies

4. SuSE

Swapping

Hello! Why does my SuSE GNU/Linux machine swap? I have a Gig of ram, currently 14MBs of free RAM, 724MB - buffers and caches... That is 685MB of cached RAM, then kernel really should'nt have to swap, It should release cached memory in my thinkin... It has only swaped 3MB's but still,... (3 Replies)
Discussion started by: Esaia
3 Replies

5. UNIX for Advanced & Expert Users

virtual memory management, swapping paging

can anybody explain me the concepts virtual memory mangement, swapping and paging? although i roughly know what they are , i need more solid distinction between them, and also i want to figure out the relations between them? do you have any well-defined definitons for this concepts? (2 Replies)
Discussion started by: gfhgfnhhn
2 Replies

6. UNIX for Dummies Questions & Answers

Swapping in VI editor

Hi, I am attempting to replace several similar words with another word in vi. Here is what I have written for the script: 3dTcat -prefix SuperBrik_4WAY_HRF ../JULY10_2007A/results2TENT/stats.JULY10_2007A+tlrc ../JULY10_2007G/results2TENT/stats.JULY10_2007G+tlrc... (1 Reply)
Discussion started by: Jahn
1 Replies

7. Shell Programming and Scripting

Swapping three lines

I have some text: <date>some_date</date> <text>some_text</text> <name>some_name<name> and I want to transform it to smthng like that: some_name on some_date: some_text I've tried sed: sed 's/<text>\(.*\)<\/text> <name>\(.*\)<\/name>/\2 - \1/' but it says unterminated... (13 Replies)
Discussion started by: dsjkvf
13 Replies

8. Shell Programming and Scripting

Swapping fields

Hallo Team, This is the command that i am running : grep ",Call Forward Not Reachable" *2013* this is the output that i am getting (i did a head -10 but the files can be more than 1000) ... (8 Replies)
Discussion started by: kekanap
8 Replies

9. Solaris

Swapping

Hi Guys I am using SPARC-T4 (chipid 0, clock 2998 MHz), SunOS 5.10 Generic_150400-38 sun4v. How do I see if the server was doing some swapping like yesterday? I had a java application error with java.lang.OutOfMemoryError, now I want to check if the server was not doing some swapping at... (4 Replies)
Discussion started by: Phuti
4 Replies

10. Shell Programming and Scripting

Swapping lines

Hi there, I have a text that I'm trying to format into something more readable. However, I'm stuck in the last step. I've searched and tried things over the internet with no avail. OS: Mac After parsing the original text that I won't put here, I managed to get something like this, but this... (8 Replies)
Discussion started by: Kibou
8 Replies
SWAPON(8)						     Linux Programmer's Manual							 SWAPON(8)

NAME
swapon, swapoff - enable/disable devices and files for paging and swapping SYNOPSIS
/sbin/swapon [-h -V] /sbin/swapon -a [-v] [-e] /sbin/swapon [-v] [-p priority] specialfile ... /sbin/swapon [-s] /sbin/swapoff [-h -V] /sbin/swapoff -a /sbin/swapoff specialfile ... DESCRIPTION
Swapon is used to specify devices on which paging and swapping are to take place. Calls to swapon normally occur in the system multi-user initialization file /etc/rc making all swap devices available, so that the paging and swapping activity is interleaved across several devices and files. Normally, the first form is used: -h Provide help -V Display version -s Display swap usage summary by device. Equivalent to "cat /proc/swaps". Not available before Linux 2.1.25. -a All devices marked as ``swap'' swap devices in /etc/fstab are made available. Devices that are already running as swap are silently skipped. -e When -a is used with swapon, -e makes swapon silently skip devices that do not exist. -p priority Specify priority for swapon. This option is only available if swapon was compiled under and is used under a 1.3.2 or later kernel. priority is a value between 0 and 32767. See swapon(2) for a full description of swap priorities. Add pri=value to the option field of /etc/fstab for use with swapon -a. Swapoff disables swapping on the specified devices and files. When the -a flag is given, swapping is disabled on all known swap devices and files (as found in /proc/swaps or /etc/fstab). NOTE
You should not use swapon on a file with holes. Swap over NFS may not work. SEE ALSO
swapon(2), swapoff(2), fstab(5), init(8), mkswap(8), rc(8), mount(8) FILES
/dev/hd?? standard paging devices /dev/sd?? standard (SCSI) paging devices /etc/fstab ascii filesystem description table HISTORY
The swapon command appeared in 4.0BSD. Linux 1.x 25 September 1995 SWAPON(8)
All times are GMT -4. The time now is 12:42 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy