Swap Management
Vhand process
If system is working with lotsfree vhand process will takeout the pages which are not recently referenced and keep it in swap to create the page for new process
Pageout
Taking the page from memory to swap by vhand
Page fault
If process try to access the address hat is not there in the memory, page fault error will come
Type of swaps
1 Primary swap
2 Secondary swap
3 Device swap
4 File system swap
Primary swap
The swap which is using while booting the system .It wall be there in the root disk.
Secondary swap.
The swap other than primary. Will be there in other disk. Will be device swap or fiesysem swap
Device swap
The space which is created for swap only. That will be a full hdd in whole disk approach or a logical volume in lvm.
File system swap
The part of the filesystem reserved for swap
Creating devicd swap
# newfs –R 200 /dev/rdsk/c0t1d0
A whole disk approach it will create a swap with size of 200 Mb . .
# lvcreate –L 200 –name newswap /dev/vg01
# /usr/sbin/swapon /dev/dsk/c0t1d0
# /usr/sbin/swapon /dev/vg01/newfs
use –f option to overwrite the old fle system
-e option to use the end of the disk.
# swapon –a to enable all the swap areas adde in /etc/fstab
Creating swap on a filesystem
# swapon –p 4 –l 12M /myfile
will create a swap wih priority 4 and limit of 12mb in the filesystem which is mounted in /myfile.
/etc/fstab
/dev/dsk/cot1d0 swap defaults 0 0
/dev/vg01/newfs swap defaults 0 0
/myfile swapfs pri=4 lim=12M 0 0
Information about swap
# swapifo –f will show all filesystem swap
# swpinfo –d will show device swap
# swapinfo –a will show all swap
# swapinfo –tm report total value in mb
# swapinfo –r will show the reserved swap
Prioritizing of swap
Priority range 0-10
-p option
# swapon –p 2 /dev/vg02/lvol3
Default priority is 1