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This article mainly shows you "what to do with the deficiency of Swap", which is easy to understand and clear. I hope it can help you solve your doubts. Let the editor lead you to study and learn the article "how to do with the deficiency of Swap".

1. Use the dd command to create a new file and mount it as SWAP

Use command 'dd' to create a file and mount as swap

[root@localhost] # free-m

Total used free shared buffers cached

Mem: 5966 334 5631 0 16 99

-/ + buffers/cache: 218 5747

Swap: 6143 0 6143

[root@localhost ~] # dd if=/dev/zero of=/root/swap bs=1024 count=1024000

1024000 million 0 records in

1024000 million 0 records out

1048576000 bytes (1.0 GB) copied, 3.20295 s, 327 MB/s

Bs= is bytes,count is blocks block, 1024bytesfolk 1K is 1024000km 1000m

[root@localhost ~] # mkswap / root/swap

Mkswap: / root/swap: warning: don't erase bootbits sectors

On whole disk. Use-f to force.

Setting up swapspace version 1, size = 1023996 KiB

No label, UUID=af12e46f-16da-4b89-a89f-301bdce4b138

[root@localhost ~] # swapon / root/swap

[root@localhost] # free-m

Total used free shared buffers cached

Mem: 5966 1604 4361 0 21 1217

-/ + buffers/cache: 365 5600

Swap: 7143 0 7143

Compared with the original one, it has increased by nearly 1000m.

two。 Format unused partitions with fdisk and mount them as swap partitions

Use 'fdisk' to format other partitions and mount as swap

[root@localhost ~] # fdisk-l

Disk / dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/ dev/sda1 * 1 13 104391 83 Linux

/ dev/sda2 14 2078 16587112 + 83 Linux

/ dev/sda3 2079 2600 4192965 82 Linux swap / Solaris

[root@localhost ~] # fdisk / dev/sda

The number of cylinders for this disk is set to 2610.

There is nothing wrong with that, but this is larger than 1024

And could in certain setups cause problems with:

1) software that runs at boot time (e.g.old versions of LILO)

2) booting and partitioning software from other OSs

(e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): P

Disk / dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/ dev/sda1 * 1 13 104391 83 Linux

/ dev/sda2 14 2078 16587112 + 83 Linux

/ dev/sda3 2079 2600 4192965 82 Linux swap / Solaris

Command (m for help): n

Command action

E extended

P primary partition (1-4)

E

Selected partition 4

First cylinder (2601-2610, default 2601):

Using default value 2601

Last cylinder or + size or + sizeM or + sizeK (2601-2610, default 2610): + 50m-add a new 50m extended partition.

-add an extend partition of 50m

Command (m for help): P

Disk / dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/ dev/sda1 * 1 13 104391 83 Linux

/ dev/sda2 14 2078 16587112 + 83 Linux

/ dev/sda3 2079 2600 4192965 82 Linux swap / Solaris

/ dev/sda4 2601 2607 56227 + 5 Extended

Command (m for help): n

First cylinder (2601-2607, default 2601):

Using default value 2601

Last cylinder or + size or + sizeM or + sizeK (2601-2607, default 2607):

Using default value 2607

Command (m for help): P

Disk / dev/sda: 21.4 GB, 21474836480 bytes

255 heads, 63 sectors/track, 2610 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System

/ dev/sda1 * 1 13 104391 83 Linux

/ dev/sda2 14 2078 16587112 + 83 Linux

/ dev/sda3 2079 2600 4192965 82 Linux swap / Solaris

/ dev/sda4 2601 2607 56227 + 5 Extended

/ dev/sda5 2601 2607 56196 83 Linux

Command (m for help): W

The partition table has been altered!

Calling ioctl () to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.

The kernel still uses the old table.

The new table will be used at the next reboot.

Syncing disks.

[root@bys3] # free-m

Total used free shared buffers cached

Mem: 2013 218 1795 0 15 153

-/ + buffers/cache: 49 1964

Swap: 5094 0 5094

[root@bys3 ~] # swapoff / root/swap closes a SWAP space

Off a swap space

[root@bys3] # free-m

Total used free shared buffers cached

Mem: 2013 218 1795 0 15 153

-/ + buffers/cache: 49 1964

Swap: 4094 0 4094

[root@bys3 ~] # mkswap / dev/sda5

/ dev/sda5: No such file or directory

[root@bys3 ~] # partprobe-synchronize partition tables

Sync of partition table

Warning: Unable to open / dev/sr0 read-write (Read-only file system). / dev/sr0 has been opened read-only.

Segmentation fault

[root@bys3 ~] # mkswap / dev/sda5

Setting up swapspace version 1, size = 57540 kB

[root@bys3 ~] # swapon / dev/sda5

[root@bys3] # free-m

Total used free shared buffers cached

Mem: 2013 218 1795 0 15 153

-/ + buffers/cache: 49 1964

Swap: 4149 0 4149

Power on and mount automatically

Auto mount during boot process

[root@localhost ~] # vi / etc/fstab

LABEL=/ / ext3 defaults 1 1

LABEL=/boot / boot ext3 defaults 1 2

Tmpfs / dev/shm tmpfs defaults 0 0

Devpts / dev/pts devpts gid=5,mode=620 0 0

Sysfs / sys sysfs defaults 0 0

Proc / proc proc defaults 0 0

LABEL=SWAP-sda3 swap swap defaults 0 0

/ root/swap swap swap defaults-dd mount method (dd mount)

/ dev/sda5 swap swap defaults 0 0-formatted mount method (formatting partition mount)

[root@localhost ~] # mount-a-mount successfully if no error is reported (No errors then mount succeed)

The above is all the content of this article "what to do with insufficient Swap". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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