Swap - Revision history

Franks: /* Creating a swap file on Ubuntu 10.10 */

2011-01-07T06:10:59Z

Creating a swap file on Ubuntu 10.10

← Older revision		Revision as of 23:10, 6 January 2011
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	$ sudo dd if=/dev/zero of=[[Variables\|/2gswap]] bs=1M count=[[Variables\|2048]]		$ sudo dd if=/dev/zero of=[[Variables\|/2gswap]] bs=1M count=[[Variables\|2048]]
	[sudo] password for franks:		[sudo] password for franks:
			2048+0 records in
			2048+0 records out
			2147483648 bytes (2.1 GB) copied, 10.7058 s, 201 MB/s

	~~2048+0 records in~~		$ sudo mkswap /2gswap
			mkswap: /2gswap: warning: don't erase bootbits sectors
			on whole disk. Use -f to force.
			Setting up swapspace version 1, size = 2097148 KiB
			no label, UUID=1a9544ea-f994-4950-bald-5d321c5455c9

			Now let's see the current swap:

			$ swapon -s

			Let's use this badboy now:

	~~2048+0 records out~~		$ sudo swapon /2gswap

	~~2147483648 bytes (2.1 GB) copied, 10.7058 s, 201 MB~~/s		You can now $ cat /proc/meminfo or:

	$ ~~sudo mkswap~~ /~~2gswap~~		$ swapon -s
	~~mkswap:~~ /~~2gswap: warning~~: ~~don't erase bootbits sectors~~
			and you should see your file. If you want to make this permanent (for it to take place after a reboot) add the following to /etc/fstab:

	~~on whole disk. Use -f to force.~~		/2gswap none swap sw 0 0

	~~Setting up swapspace version 1~~, ~~size = 2097148 KiB~~		Done! Check out your memory situation, including your new swap:

	~~no label, UUID=1a9544ea-f994-4950-bald-5d321c5455c9~~		$ free

Franks at 06:04, 7 January 2011

2011-01-07T06:04:21Z

← Older revision		Revision as of 23:04, 6 January 2011
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	System Preferences -> Security pane and choose "Use secure virtual memory"		System Preferences -> Security pane and choose "Use secure virtual memory"


			== Creating a swap file on Ubuntu 10.10 ==

			This creates a 2G file called /2gswap. Change the name, location and size as you wish:

			$ sudo dd if=/dev/zero of=[[Variables\|/2gswap]] bs=1M count=[[Variables\|2048]]
			[sudo] password for franks:

			2048+0 records in

			2048+0 records out

			2147483648 bytes (2.1 GB) copied, 10.7058 s, 201 MB/s

			$ sudo mkswap /2gswap
			mkswap: /2gswap: warning: don't erase bootbits sectors

			on whole disk. Use -f to force.

			Setting up swapspace version 1, size = 2097148 KiB

			no label, UUID=1a9544ea-f994-4950-bald-5d321c5455c9

Franks at 09:24, 18 October 2007

2007-10-18T09:24:45Z

← Older revision		Revision as of 02:24, 18 October 2007
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	If you are running out of swapspace frequently, or just want to increase the capacity, you can [http://www.freebsd.org/handbook/adding-swap-space.html add a swapfile ]very easily on [[FreeBSD]].		If you are running out of swapspace frequently, or just want to increase the capacity, you can [http://www.freebsd.org/handbook/adding-swap-space.html add a swapfile ]very easily on [[FreeBSD]].


			----
			[http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/swap-encrypting.html Encrypting swap in FreeBSD] has existed since version 5.3




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	$ cat /proc/swaps		$ cat /proc/swaps


			== Encrypting swap in MacOSX ==

			System Preferences -> Security pane and choose "Use secure virtual memory"

Franks at 09:19, 18 October 2007

2007-10-18T09:19:26Z

← Older revision		Revision as of 02:19, 18 October 2007
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	Swap a secondary storage for [[memory]] that is swapped or paged out, usually residing on your hard disk.		Swap is a secondary storage for [[memory]] that is swapped or paged out, usually residing on your hard disk. Hard drives are a lot slower to read and write to than [[RAM]], so ideally you will want to increase your RAM if financially possible if you see that your swap is being used, assuming speed as priority.

	It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't (such as [[BSD]]), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.		It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't (such as [[BSD]]), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.

Franks: /* Encrypting your swap in GNU/Linux */ typo

2007-10-18T09:15:38Z

Encrypting your swap in GNU/[[Linux]]: typo

← Older revision		Revision as of 02:15, 18 October 2007
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	and then added the following to /etc/fstab:		and then added the following to /etc/fstab:

	/dev/mapper/swap swap sw 0 0		/dev/mapper/swap none swap 0 0

	finally, I ran:		finally, I ran:

Franks: /* Encrypting your swap in GNU/Linux */

2007-09-27T23:33:35Z

Encrypting your swap in GNU/[[Linux]]

← Older revision		Revision as of 16:33, 27 September 2007
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	== Encrypting your swap in GNU/[[Linux]] ==		== Encrypting your swap in GNU/[[Linux]] ==

	This was done on [[Ubuntu]] feisty fawn. I added this to /etc/crypttab:		This was done on [[Ubuntu]] feisty fawn. If you're doing this on your live system, first deactivate your current swap:

			# swapoff -a

			I added this to /etc/crypttab:

	swap /dev/[[Variables\|sda2]] /dev/urandom cipher=aes-cbc-essiv:sha256,hash=sha256,size=256,swap		swap /dev/[[Variables\|sda2]] /dev/urandom cipher=aes-cbc-essiv:sha256,hash=sha256,size=256,swap

Franks: /* Encrypting your swap in GNU/Linux */

2007-09-27T22:23:44Z

Encrypting your swap in GNU/[[Linux]]

← Older revision		Revision as of 15:23, 27 September 2007
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	to see if it's working:		to see if it's working:

	$ swapon -s ~~lists~~		$ swapon -s

	or		or

	$ cat /proc/swaps		$ cat /proc/swaps

Franks at 22:20, 27 September 2007

2007-09-27T22:20:37Z

← Older revision		Revision as of 15:20, 27 September 2007
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	If you are running out of swapspace frequently, or just want to increase the capacity, you can [http://www.freebsd.org/handbook/adding-swap-space.html add a swapfile ]very easily on [[FreeBSD]].		If you are running out of swapspace frequently, or just want to increase the capacity, you can [http://www.freebsd.org/handbook/adding-swap-space.html add a swapfile ]very easily on [[FreeBSD]].



			== Encrypting your swap in GNU/[[Linux]] ==

			This was done on [[Ubuntu]] feisty fawn. I added this to /etc/crypttab:

			swap /dev/[[Variables\|sda2]] /dev/urandom cipher=aes-cbc-essiv:sha256,hash=sha256,size=256,swap

			and then added the following to /etc/fstab:

			/dev/mapper/swap swap sw 0 0

			finally, I ran:

			$ sudo /etc/init.d/cryptdisks start
			$ swapon -a

			to see if it's working:

			$ swapon -s lists

			or

			$ cat /proc/swaps

Frankk at 19:42, 27 October 2005

2005-10-27T19:42:00Z

← Older revision		Revision as of 12:42, 27 October 2005
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	Is a secondary storage for [[memory]] that is swapped or paged out. It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't ([[BSD]] ~~doesn't~~), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.		Swap a secondary storage for [[memory]] that is swapped or paged out, usually residing on your hard disk.

			It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't (such as [[BSD]]), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.

			Don't forget to ensure there is always enough room in your swap if your RAM is being used to its maximum capacity:
			# swapinfo
			Device 1K-blocks Used Avail Capacity
			/dev/ad0s1b 105288 68596 36692 65%

			otherwise you'll start getting errors to syslog, running applications will be killed, and it will create a general
			mess of things:

			Oct 27 09:51:38 mail swap_pager_getswapspace(9): failed
			Oct 27 09:51:38 mail swap_pager_getswapspace(5): failed
			Oct 27 09:51:38 mail swap_pager_getswapspace(16): failed
			Oct 27 09:51:40 mail pid 95400 (perl5.8.7), uid 125, was killed: out of swap space

			If you are running out of swapspace frequently, or just want to increase the capacity, you can [http://www.freebsd.org/handbook/adding-swap-space.html add a swapfile ]very easily on [[FreeBSD]].

Frankk at 19:37, 27 October 2005

2005-10-27T19:37:56Z

← Older revision		Revision as of 12:37, 27 October 2005
Line 1:		Line 1:
	Is a secondary storage for memory that is swapped or paged out. It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't ([[BSD]] doesn't), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.		Is a secondary storage for [[memory]] that is swapped or paged out. It is also used for saving the [[kernel]] [[core]]file when the system [[panic]]s. Some systems compress their corefile to swap and others don't ([[BSD]] doesn't), this is why it's a good idea to have 1.5 to 2 times as much swap as physical memory in a machine (as a rule of thumb), so that you can get a good corefile.