How to Allocate More Space to Swap and Increase its Size Greater than Ram?
Solution 1
You just want to increase the swap size on your system using the space from sda2
. Your sda2
/dev/sda2 104G 74G 25G 75% /
You can add additional swap space to your system by using swap file created on /
that will utilize your sda2
. Just do:
dd if=/dev/zero of=/swapfile bs=20480 count=1M
and then do:
sudo mkswap /swapfile
sudo swapon /swapfile
and check, you swap space will increase by that amount using free -m
and yes , to enable it at boot time add the entry in /etc/fstab
/swapfile none swap sw 0 0
Solution 2
You question, "How to Allocate More Space to Swap and Increase its Size Greater than Ram?", does not say anything about changing the way your system is set up.
Your fdisk and free output tells us:
- You have a a partition (/dev/sda3) dedicated to swap. If you just resize that partition you should not need to change anything in your system to use the extra space. (/etc/fstab).
- You have a partition (/dev/sda2) that has the OS on it. This partition has 26G free space. If you shrink this partition by 20G the OS will have 5G left to grow and use.
The swap partition is not a extended partition, this makes it a little bit easier to increase the size.
Tools required:
- Bootable OS with gparted
Look here for one location of the last free version of Parted Magic
Instruction for resizing partitions with gparted
- boot into another OS that has gparted tool
- In gparted; resize OS partition (/dev/sda2). Shrink by amount to donate to swap space. This could take a lot of time because all of the data that is in the space being freed up will need to be moved by gparted.
- In gparted; resize swap partition (/dev/sda3). Move and extend to include all free space.
- reboot into sda2 OS.
- verify swap partition (/dev/sda3) is being used.
Remember that you are changing you disk and partitions on a low level and that any errors or crashes could damage you data.
Backup you data first.
Related videos on Youtube
![Léo Léopold Hertz 준영](https://i.stack.imgur.com/0VZ1V.png?s=256&g=1)
Léo Léopold Hertz 준영
Updated on September 18, 2022Comments
-
Léo Léopold Hertz 준영 almost 2 years
Situation: increase swap size (
/dev/sda3
) greater than Ram (8 GB) when HD 128 GB
Motivation: 8 GB RAM is too little; 30 GB free space in my SSD; I want to turn 20 GB to SSD swap
Characteristics of system-
Swap non-immutable/changeable. I cannot find any evidence why
/mnt/.swapfile
should be immutable so you do not need the change the file attributes of the swapfilesudo lsattr /mnt/.swapfile -------------e-- /mnt/.swapfile
-
Command
sudo fdisk -lu /dev/sda
givesDisk /dev/sda: 113 GiB, 121332826112 bytes, 236978176 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: 082F85CA-EE3E-479C-8244-858B196FA5BA Device Start End Sectors Size Type /dev/sda1 2048 4095 2048 1M BIOS boot /dev/sda2 4096 220323839 220319744 105.1G Linux filesystem /dev/sda3 220323840 236976127 16652288 8G Linux swap
-
Command
df -h
givesFilesystem Size Used Avail Use% Mounted on udev 3.9G 0 3.9G 0% /dev tmpfs 793M 9.4M 784M 2% /run /dev/sda2 104G 74G 25G 75% / tmpfs 3.9G 54M 3.9G 2% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup tmpfs 793M 64K 793M 1% /run/user/1000
Allocate more disk space for Swap in
/dev/sda3
.
My unsuccessful workflow for the task when HD and Swap on the same partition,
/dev/sda3
masi@masi:~$ sudo -i root@masi:~# swapoff /dev/sda3 root@masi:~# swapon [blank] root@masi:~# dd if=/dev/zero of=/dev/sda3 bs=20480 count=1M dd: error writing '/dev/sda3': No space left on device 416308+0 records in 416307+0 records out 8525971456 bytes (8.5 GB, 7.9 GiB) copied, 18.7633 s, 454 MB/s root@masi:~# mkswap /dev/sda3 Setting up swapspace version 1, size = 8 GiB (8525967360 bytes) no label, UUID=245cb42c-1d4e-4e21-b544-16b64af962d6 root@masi:~# swapon -p 99 /dev/sda3 root@masi:~# swapon NAME TYPE SIZE USED PRIO /dev/sda3 partition 8G 0B 99 root@masi:~# vi /etc/fstab ...
HD and Swap on same Partition - Current Workflow [Ijaz, cas, FarazX]
Merging. Use
fallocate
at the beginning insteaddd
because no need to put zerosmasi@masi:~$ sudo fallocate -l 20G /mnt/.swapfile masi@masi:~$ sudo mkswap /mnt/.swapfile Setting up swapspace version 1, size = 20 GiB (21474832384 bytes) no label, UUID=45df9e48-1760-47e8-84d7-7a14f56bbd72 masi@masi:~$ sudo swapon /mnt/.swapfile swapon: /mnt/.swapfile: insecure permissions 0644, 0600 suggested. masi@masi:~$ sudo chmod 600 /mnt/.swapfile masi@masi:~$ free -m total used free shared buff/cache available Mem: 7925 1494 175 196 6255 5892 Swap: 28610 0 28610
Add the following line in your
/etc/fstab
which is better than adding the thing to your runlevels (/etc/rc.local
), where I put the swapfile to the/mnt/.swapfile
to maintain Linux/Unix philosophy and maintain the integrity of my system backup scripts; If swapping to an SSD, use thediscard
option so that the blocks are trimmed on every reboot, so notsw
# http://unix.stackexchange.com/a/298212/16920 # http://unix.stackexchange.com/a/298543/16920 # If swap is on SSD, trim blocks each time at startup. /mnt/.swapfile none swap defaults,discard 0 0 # If swap on External HDD, just use sw. #/media/masi/SamiWeek/.swapfile none swap sw 0 0
Sources
- How to increase swap space? https://askubuntu.com/a/178726/25388 General discussion about increasing swap space for beginners.
- Linux Partition HOWTO for HDDs, not SSDs: 4. Partitioning requirements. http://www.tldp.org/HOWTO/Partition/requirements.html So do not put your swap to outer tracks on SSDs but use
defaults,discard
options to trim your blocks as proposed by @cas.
System: Linux Ubuntu 16.04 64 bit
Linux kernel: 4.6
Linux modules:wl
Hardware: Macbook Air 2013-mid
Ram: 8 GB
SSD: 128 GB-
Admin almost 8 yearsOutput of
fdisk -lu /dev/sda
? -
Admin almost 8 yearsOptions are shrinking fs on /dev/sda2 and repartition (but that can't be done from the live system as you can't unmount /dev/sda2 as that's the root filesystem: boot on some livecd is the easiest), or use a swap file as opposed to block device, or use compressed swap or compressed ram
-
Admin almost 8 yearsFew of those placement considerations apply to SSD:s, as they don't have heads or tracks like spinning disks. Striping over multiple drives might apply, if you have a huge I/O load.
-
-
Lmwangi almost 8 yearsYep, you should be able to compute. Swapper should see a large virtual memory.
-
roaima almost 8 years@masi if you add an entry in
/etc/fstab
you can avoid the entries inrc.local
. Put the swap file somewhere like/mnt/.swap
and you'll not need to worry about it too much any more -
Admin almost 8 years@Masi no, fallocate is just easire, no need to put zeros and set count via
dd
since you might do it wrong if you don't know what you are doing,dd
is a super-powerfull command. And AFAIK Swap space in Linux is used when the amount of physical memory (RAM) is full, and be aware that is has no mount point. So I think it doesn't matter where it is, just chmod it to 600. -
Admin almost 8 years@Masi my pleasure. BTW, you can read about fields in
fstab
by runningman 5 fstab
. Good Luck mate. -
Léo Léopold Hertz 준영 almost 8 yearsI think you do not need
gparted
here because you can put swab in the same disk where your OS is. -
jc__ almost 8 yearsTrue, but then you would have 2 swap. File on /sda2 and partition on /sda3. This answers the part of the question that asked "Allocate more disk space for Swap in /dev/sda3. How to take it from /dev/sda2?".
-
jc__ almost 8 yearsIn reference to the statement: "However, not sure because I think /dev/sda2 and /dev/sad3 are on the same disk partition".
/dev/sda2
and/dev/sda3
are separate partitions. -
jc__ almost 8 yearsSo you are adding another device that has space on it you want to use for swap? If yes. You could create a new partition of type swap on it and when plugged in and ready to use do a
swapon
or similar. On device removal do aswapoff
or similar. Device swap status will not be remembered on OS reboot. -
jc__ almost 8 yearsOr create an ext type partition on new device, create the swap file and a script to turn on swap file with required settings and a script to turn off swap file. This would allow you to only use the extra swap space when needed.
-
jc__ almost 8 yearsAfter you create the partition you can format it with
mkfs
. After that mount it on the running OS. -
Léo Léopold Hertz 준영 almost 8 yearsHow is
mkfs
different fromchattr
? -
jc__ almost 8 yearsmkfs will format a partition with a file system. (vfat, ext2, ext4, ntfs). chattr will change the file attributes of a file on an ext file system.
-
Admin almost 8 years@Masi yes of course. You can list file attributes by
lsattr
, and as I mentioned you can set them bychattr
. For instance, if you wanna make it immutable, you can usechattr +i /mnt/.swapfile
, or in BSD or OS X you can usechflags uchg yourFile
. You have many attribute options, for instance, when a file withs
attribute set is deleted, its blocks will be zeroed and written back to the disk. But I recommend you read its manual page and surf the net about. It's not as easy as it seems to usechattr
, and you should be aware of what you are really going to do! -
jc__ almost 8 yearsNOTE: when creating a swap type partition it does not need to be formated, but most others must be formated with the file system. Gparted will format at the same time it creates the partition so no further action required.
-
Admin almost 8 years@Masi AFAIK setting attribute is up to your needs, so the answer is no for the majority systems. But you can find some Unix-Like operating systems having some files or directories with immutable or restricted attributes set by default, for Instance, MacOS X.
-
jc__ almost 8 yearsIt is true that you do not need to use mkfs or chattr if you use the same partition and resize it as described in this answer. If you create a swap file on the same partition as your OS, No mkfs is not needed because there is already a file system. chattr; I am not familiar with.
-
Admin almost 8 years@Masi in fact, there is no need of doing it by default, so I think the answer is no, since Swapfiles are most likely used temporarily not permanently. If you are using LVM partitions it's better to increase your swap partition, instead of making a swapfile. But if you cannot do that and swapfiles are the only option, there is no problem, but it will affect your system and does slow its performance. There is no rule-book, everything depends on your needs, and what you can do for it, and how secure you want your system to be.