How to Allocate More Space to Swap and Increase its Size Greater than Ram?

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 swapfile
```
sudo lsattr /mnt/.swapfile 
-------------e-- /mnt/.swapfile
```

Command sudo fdisk -lu /dev/sda gives

Disk /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 gives

Filesystem      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

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="422f23312b022f23312b">[email protected]</a>:~$ sudo -i

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="295b46465d6944485a40">[email protected]</a>:~# swapoff /dev/sda3

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="fb8994948fbb969a8892">[email protected]</a>:~# swapon
[blank]    

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="72001d1d06321f13011b">[email protected]</a>:~# 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

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8ffde0e0fbcfe2eefce6">[email protected]</a>:~# mkswap /dev/sda3
Setting up swapspace version 1, size = 8 GiB (8525967360 bytes)
no label, UUID=245cb42c-1d4e-4e21-b544-16b64af962d6

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e694898992a68b87958f">[email protected]</a>:~# swapon -p 99 /dev/sda3

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="b2c0ddddc6f2dfd3c1db">[email protected]</a>:~# swapon
NAME       TYPE      SIZE USED PRIO
/dev/sda3  partition   8G   0B   99

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="9ceef3f3e8dcf1fdeff5">[email protected]</a>:~# vi /etc/fstab 
...

Contents hide

HD and Swap on same Partition – Current Workflow [Ijaz, cas, FarazX]

Answers:

Method 1

Method 2

Method 3

HD and Swap on same Partition – Current Workflow [Ijaz, cas, FarazX]

Merging. Use fallocate at the beginning instead dd because no need to put zeros

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="aec3cfddc7eec3cfddc7">[email protected]</a>:~$ sudo fallocate -l 20G /mnt/.swapfile

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="4d202c3e240d202c3e24">[email protected]</a>:~$ sudo mkswap /mnt/.swapfile 
Setting up swapspace version 1, size = 20 GiB (21474832384 bytes)
no label, UUID=45df9e48-1760-47e8-84d7-7a14f56bbd72

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="513c302238113c302238">[email protected]</a>:~$ sudo swapon /mnt/.swapfile
swapon: /mnt/.swapfile: insecure permissions 0644, 0600 suggested.

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="9df0fceef4ddf0fceef4">[email protected]</a>:~$ sudo chmod 600 /mnt/.swapfile

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="ec818d9f85ac818d9f85">[email protected]</a>:~$ 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 the discard option so that the blocks are trimmed on every reboot, so not sw

# 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

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 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

Method 2

Memory management
- To display swap usage summary by your device:
```
$ swapon -s
```
- To displays the amount of your free and used physical and swap memory:
```
$ free -h
```
- To preallocate space to /swapfile, you can use the line below:
```
$ fallocate -l 20G /swapfile
% OR
$ dd if=/dev/zero of=/swapfile bs=20480 count=1M
```
Change permission and create/activate swap
```
$ chmod 600 /swapfile

$ mkswap /swapfile

$ swapon /swapfile
```
You can also improve your file security by changing your file attributes using chattr. I recommend you read its manual page, or read this guide on Tecmint website.
Verify it is enabled by viewing the output of the command cat /proc/swaps, use free command, or
```
$ swapon -s
```
To enable it at boot time, edit /etc/fstab (static information about the file system) to include the following where the fields are fs_spec, fs_file, fs_vfstype, fs_mntops, fs_freq and fs_passno, about which you can read by man 5 fstab:
```
$ vi /etc/fstab

/swapfile     none     swap     defaults,discard     0     0
```
- In the fourt parameter fs_mntops, do not use just sw when swapping to an SSD but defaults,discard such that the memory blocks are trimmed each time at startup, see the answer here about How to Do Error-trapping and Swapoff if Error/Warning?
  The discard option definitely works on partitions.

Method 3

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.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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