Memory issues - Revision history

Neteler: RAM: explain 32-bit memory constraints

2016-10-02T12:22:59Z

RAM: explain 32-bit memory constraints

← Older revision		Revision as of 12:22, 2 October 2016
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			== RAM issues ==

			Q: I get a message ''"ERROR: G_realloc: unable to allocate 52980000 bytes of memory at lib/vector/diglib/cindex.c:113"'' or similar? What's up?

			A: Is your local GRASS GIS built for 32-bit (x86) or 64-bit (x86-64 aka amd64)? Running the "file" command (Unix systems only) on e.g. <tt>r.contour</tt> will tell you:

			# run next line in a GRASS GIS session:
			file `which r.contour`

			A 32-bit process can't use more than 4 GiB of memory regardless of how much RAM or swap is available. The amount available to malloc() etc will be somewhat lower due to reservations for the kernel, stack, etc.

			If you run a 64bit GRASS GIS version on a 64 bit system, then check [[Large raster data processing#Troubleshooting]]. Otherwise use less data or get a 64 bit system...

	== Memory limits on MS-Windows ==		== Memory limits on MS-Windows ==

Neteler: +Memory limits on MS-Windows

2016-06-09T07:32:46Z

+Memory limits on MS-Windows

← Older revision		Revision as of 07:32, 9 June 2016
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	~~''thanks~~ to ~~Gordon Keith for these tips''~~		== Memory limits on MS-Windows ==

			* Please refer to: https://msdn.microsoft.com/en-us/library/aa366778.aspx

	== Adding temporary swap space in Linux ==		== Adding temporary swap space in Linux ==

			''thanks to Gordon Keith for these tips''

	<!-- http://grass.itc.it/pipermail/grassuser/2002-June/006700.html -->		<!-- http://grass.itc.it/pipermail/grassuser/2002-June/006700.html -->

Neteler at 22:38, 14 January 2015

2015-01-14T22:38:10Z

← Older revision		Revision as of 22:38, 14 January 2015
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	It doesn't solve all out-of-memory problems, but may make it less painful. There is probably something similar on other platforms, but the mechanics may differ (eg under csh: limit vm 20000m).		It doesn't solve all out-of-memory problems, but may make it less painful. There is probably something similar on other platforms, but the mechanics may differ (eg under csh: limit vm 20000m).

			== See also ==

			* [[Large raster data processing#Troubleshooting]]

	[[Category:FAQ]]		[[Category:FAQ]]
	[[Category: massive data analysis]]		[[Category: massive data analysis]]

⚠️Madi at 12:46, 14 August 2012

2012-08-14T12:46:45Z

← Older revision		Revision as of 12:46, 14 August 2012
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	[[Category:FAQ]]		[[Category:FAQ]]
			[[Category: massive data analysis]]

⚠️HamishBowman: /* Adding temporary swap space in Linux */ modernize

2011-05-30T05:30:19Z

Adding temporary swap space in Linux: modernize

← Older revision		Revision as of 05:30, 30 May 2011
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	The file can reside anywhere on the local file system, so long as it it		The file can reside anywhere on the local file system, so long as it it
	created using the preceding commands. On a faster disk is of course		created using the preceding commands. On a faster disk is of course
	better for performance. Swapfiles bigger than 2GB only work on ~~very~~		better for performance. Swapfiles bigger than 2GB only work on
	recent kernels, so I'd recommend sticking with 2GB or less and use more		recent kernels, so if you have an older system I'd recommend sticking with 2GB or less and use more
	than one if you want more than 2GB extra swap space. (I used 2x2GB		than one if you want more than 2GB extra swap space. (I used 2x2GB
	swapfiles and a 1.5GB swap partition when I was playing with		swapfiles and a 1.5GB swap partition when I was playing with
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	the swapfile. See man pages for mkswap, swapon and swapoff for		the swapfile. See man pages for mkswap, swapon and swapoff for
	details.		details.


	== Limiting process memory usage in Linux ==		== Limiting process memory usage in Linux ==

⚠️HamishBowman: /* Limiting process memory usage in Linux */ edits

2008-11-09T23:50:10Z

Limiting process memory usage in Linux: edits

← Older revision		Revision as of 23:50, 9 November 2008
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	== Limiting process memory usage in Linux ==		== Limiting process memory usage in Linux ==

	On Linux using bash it can be useful to limit the amount of memory any process can have so that if I get the size wrong the job dies rather than tying up the machine.		On Linux using bash it can be useful to limit the amount of memory any process can have so that if you get the region size wrong the job dies rather than tying up the machine.

	For example my .bashrc on our shared server has:		For example my .bashrc on our shared server has:

⚠️HamishBowman: limiting process mem usage in linux (another from GK)

2008-11-09T23:47:58Z

limiting process mem usage in linux (another from GK)

@@ Line 1: / Line 1: @@
 == Adding temporary swap space in Linux ==
 <!-- http://grass.itc.it/pipermail/grassuser/2002-June/006700.html -->
@@ Line 37: / Line 38: @@
 the swapfile.  See man pages for mkswap, swapon and swapoff for
 details.
 [[Category:FAQ]]

⚠️HamishBowman: /* Adding temporary swap space in Linux */

2007-06-10T10:12:08Z

Adding temporary swap space in Linux

← Older revision		Revision as of 10:12, 10 June 2007
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	== Adding temporary swap space in Linux ==		== Adding temporary swap space in Linux ==
	''thanks to Gordon Keith''		''thanks to Gordon Keith for this tip''

	<!-- http://grass.itc.it/pipermail/grassuser/2002-June/006700.html -->		<!-- http://grass.itc.it/pipermail/grassuser/2002-June/006700.html -->

⚠️HamishBowman: init

2007-06-10T10:11:50Z

init

New page

== Adding temporary swap space in Linux ==
''thanks to Gordon Keith''



To monitor your swap usage you can use utilities like top, xosview etc
(they're the ones I use, but there are many others that will do the
job).

If you are running out of swap space it is fairly easy to create a swap
file and add it to your current swap area:

su
dd if=/dev/zero of=/var/swapfile bs=1024 count=2048000
mkswap /var/swapfile
swapon /var/swapfile

Will create a 2GB (approx) swapfile called /var/swapfile, format it as
swapfile and add it to the swap space.

The file can reside anywhere on the local file system, so long as it it
created using the preceding commands. On a faster disk is of course
better for performance. Swapfiles bigger than 2GB only work on very
recent kernels, so I'd recommend sticking with 2GB or less and use more
than one if you want more than 2GB extra swap space. (I used 2x2GB
swapfiles and a 1.5GB swap partition when I was playing with
s.surf.idw).

If you no longer need the swap space but need the disk space you can
free it with:

su
swapoff /var/swapfile
rm /var/swapfile

The swapoff command will only work when there are no pages currently in
the swapfile. See man pages for mkswap, swapon and swapoff for
details.

[[Category:FAQ]]