AIX training notes-swap space

Swap space, that is, virtual memory in the operating system. This article briefly introduces some basic commands for swap space management.

 

Swap space allocation principles:

Only one paging space per disk;

Use disks with the least activity;

Paging spaces roughly the same size;

Do not extend paging space to multiple physical volumes;

Use multiple disk controllers;

View swap space usage:

# LSPs-

Page Space
Physical Volume
Volume Group
Size % used active
Auto
Type

Paging00
Hdisk4
Rootvg
8192 MB
31
Yes
Yes
LV

Hd6
Hdisk3
Rootvg
8192 MB
31
Yes
Yes
LV

View the number of physical memory:

# Lsattr-El sys0-A realmem

Realmem 33554432 amount of usable physical memory in Kbytes false

Or:

# Lsattr-El mem0

Goodsize 32768 amount of usable physical memory in Mbytes false

Size
32768 total amount of physical memory in Mbytes
False

View the swap space activated when the system starts:

# Cat/etc/swapspaces

*/Etc/swapspaces

*

* This file lists all the paging spaces that are automatically put

* Service on each system restart (the 'swapon-a' command executed from

*/Etc/rc swaps on every device listed here ).

*

* Warning: Only paging Space Devices shoshould be listed here.

*

* This file is modified by the CHPs, mkps and RMPs commands and referenced

* By the LSPs and Swapon commands.

Hd6:

Dev =/dev/hd6

Paging00:

Dev =/dev/paging00

 

Pay special attention to the following information. Once discovered, the system administrator should be notified immediately for handling:

"Init: Paging space is low"

"KSh: cannot fork no swap space"

"Not enough memory"

"Fork function failed"

"Fork () System Call failed"

"Unable to fork, too may processes"

"Fork failure-not enough memory available"

"Fork function not allowed. Not enough memory available ."

"Cannot fork: not enough space"

 

You can use
Smit
Or
Mkps
Command to complete,
Mkps
The command format is as follows:

Mkps [-A] [-N] [-T type]-s numlps vgname pvname

Vgname



The volume group (
Volume Group
) Name

Pvname



The physical volume of the swap space (
Physical Volume
) Name

-S numlps

The logical partition occupied by the swap space (
Logical Partition
)

-

Activate the anti-bot service when the system starts the next time.
(
Add the swap space
/Etc/swapspaces

File
)

-N

Activate the swap space now

-T Type

Specify the type of the swap space (
LV
Or
NFS
)

The following command is named
Rootvg
Volume Group
(
Volume Group
)
Create
4
Logical partitions
(
Logical Partition
)
The size of the swap space. Activate the swap space immediately after creation and activate the swap space the next time the system starts:

 

# Mkps-S 4-n-A rootvg

After the command is executed
/Dev/pagingnn
A swap space, where
Nn
Is a sequence number, such
00
,
01
.

 

If the swap space is not activated when it is created, use the following command to activate it:

# Swapon
/Dev/paging00

Swap-
Command can be activated
/Etc/swapspaces
All swap spaces defined in. This command is generally automatically executed when the system starts.

 

The following command changes an activated swap space to inactive:

# Swapoff
/Dev/paging00

This command may be caused
I/O
Error or insufficient swap space
Paging00
Failed.

 

You can use the following command to dynamically modify the size of a swap space:

# CHPs-D 1 paging00


#
From swap space
Paging00
Deleting
1
Items
Lp
;

# CHPs-S 1 paging00


#
To swap space
Paging00
Add
1
Items
Lp
;

Note: This command cannot make the primary swap space (usually
Hd6
)
Less than 32 MB.

 

The following command can be used to delete a swap space:

# RMPs paging00

Before deleting a swap space, the swap space must be inactive.