Hi guys, Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days? Thanks Hans
On Friday 06 October 2006 01:35, Hans du Plooy wrote:
Hi guys,
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
According to: http://www.lissot.net/partition/partition-04.html#SwapSize the limit is architecture-dependent, but is "officially" 2GB on i386, with this note to qualify "officially": "max swap size: With kernel 2.4, the limit is 64 swap spaces at a maximum of 64Gb each, although this is not reflected in the man page for mkswap. With the 64 bit opteron on the 2.6 kernel, 128 swap areas are permitted, each a whopping 16 Tb!" -- ----- stephan@s11n.net http://s11n.net "...pleasure is a grace and is not obedient to the commands of the will." -- Alan W. Watts
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Friday 2006-10-06 at 01:35 +0200, Hans du Plooy wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
No, I have a 6 GiB swap. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFJZv2tTMYHG2NR9URAn62AJ4ybYFpBWyWrLekyOPyd6rfI8SRGwCfRpn7 ilLU6K+NAQZJdLCisrDnKUw= =0qlg -----END PGP SIGNATURE-----
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB. What I meant is is the size of a single swap partition still limited to 2GB? Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap. Thanks Hans
no my PC, I have 1 swap partition with 3GB of swap.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Friday 2006-10-06 at 08:16 +0200, Hans du Plooy wrote:
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB.
What I meant is is the size of a single swap partition still limited to 2GB?
Then I worded my answer poorly: my 6 GiB swap are in a single partition :-) I don't know the limit or if there is one. There were two previously: the kernel and the swap area format itself.
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You can do it, no problem - on that side at least :-) - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFJhuZtTMYHG2NR9URAsdHAJ9s++gpRP8/s5+g3j7NHsfY+GiNXwCgk0vW XOoNfWz5EqM66kW59jqb+x4= =GH9I -----END PGP SIGNATURE-----
Hans du Plooy wrote:
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days? No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB.
What I meant is is the size of a single swap partition still limited to 2GB?
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You can have multiple swap partitions and even use swap files.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Friday 2006-10-06 at 07:29 -0400, James Knott wrote:
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You can have multiple swap partitions and even use swap files.
Not for suspend to disk, unfortunately. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFJkPBtTMYHG2NR9URApAFAJ4rvmqR4f5iA3c2ETqcffIvd55nhwCbBT9+ bAP5E9X8Aa3Y74wIrhPKYm4= =Z+vQ -----END PGP SIGNATURE-----
On Fri, 2006-10-06 at 07:29 -0400, James Knott wrote:
Hans du Plooy wrote:
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days? No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB.
What I meant is is the size of a single swap partition still limited to 2GB?
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You can have multiple swap partitions and even use swap files.
I know but can I pass mutltiple swapfiles to the kernel for resuming? I'm not sure how that would work. The object is to get a successful resume after suspend to disc (see my other thread on HP nx6125). It is my understanding that the entire contents of the memory should fit into a single swap partition for resuming. For normal usage I have more than enough swop - hardly use it ever. Hans
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Friday 2006-10-06 at 14:02 +0200, Hans du Plooy wrote:
You can have multiple swap partitions and even use swap files.
I know but can I pass mutltiple swapfiles to the kernel for resuming?
The scripts detect that condition and abort the suspend process. At least, they did that when I tried a year or two ago. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFJlugtTMYHG2NR9URAkcRAJ9wD6bFm7KC3sZFTzmctKOz0dTycACcD9H8 +qHAe/VbBIEvuvWdGv014L4= =lrPk -----END PGP SIGNATURE-----
James Knott wrote:
Hans du Plooy wrote:
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB.
What I meant is is the size of a single swap partition still limited to 2GB?
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You can have multiple swap partitions and even use swap files.
This is probably picky. But I think the subject line for this discussion is incorrect. Swap is not a filesystem. It does take a partition but it is raw disk storage not a filesystem as far as I know.
On Friday 06 October 2006 10:37, Robert Lewis wrote:
James Knott wrote:
You can have multiple swap partitions and even use swap files.
This is probably picky. But I think the subject line for this discussion is incorrect. Swap is not a filesystem. It does take a partition but it is raw disk storage not a filesystem as far as I know.
You are correct for swap partitions. Linux does allow using a swap file though, which can come in very handy; you don't want to repartition your hard drive (512MB to 2GB memory upgrade) for a larger swap file (you use suspend-to-disk and your swap partition is only 1GB) but you have extra space on a partition. Create a swap file of > 2GB to hold suspend-to-disk. Stan
On Fri, 2006-10-06 at 08:16 +0200, Hans du Plooy wrote:
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
Probably i'm missing something... On most systems i encounter, much of the memory is used by buffers or cache. What's the point of writing that info back to a swap partition, (as it is already somewhere on disk anyhow) Hans -- pgp-id: 926EBB12 pgp-fingerprint: BE97 1CBF FAC4 236C 4A73 F76E EDFC D032 926E BB12 Registered linux user: 75761 (http://counter.li.org)
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Monday 2006-10-09 at 00:03 +0200, Hans Witvliet wrote:
What's the point of writing that info back to a swap partition, (as it is already somewhere on disk anyhow)
It is not written. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFKYVgtTMYHG2NR9URAlVTAKCUTLACsnMyw/vjKU5o+E9lHcXWZwCghKIh 8bPbL6Orh8C+xHRnDF2t8q0= =bth2 -----END PGP SIGNATURE-----
On Mon, 2006-10-09 at 01:10 +0200, Carlos E. R. wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
The Monday 2006-10-09 at 00:03 +0200, Hans Witvliet wrote:
What's the point of writing that info back to a swap partition, (as it is already somewhere on disk anyhow)
It is not written.
After a "sync" all unwritten buffers should be commited to disk (according to man&info) It should not only limit the amount of needed swap-space, but also speed-up suspend & resume, not?
-- pgp-id: 926EBB12 pgp-fingerprint: BE97 1CBF FAC4 236C 4A73 F76E EDFC D032 926E BB12 Registered linux user: 75761 (http://counter.li.org)
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Monday 2006-10-09 at 08:10 +0200, Hans Witvliet wrote:
The Monday 2006-10-09 at 00:03 +0200, Hans Witvliet wrote:
What's the point of writing that info back to a swap partition, (as it is already somewhere on disk anyhow)
It is not written.
After a "sync" all unwritten buffers should be commited to disk (according to man&info)
I meant that it is not written as swap. Processes are stopped, pending disk operations are committed, then as much ram as possible is freed. The remainder is saved to swap, just as would be swapped out processes, I guess.
It should not only limit the amount of needed swap-space, but also speed-up suspend & resume, not?
It would probably be faster to read everything from swap, as it is a contiguous disk area, than reading everything as needed from all over the disk. The wake up process is way faster than a boot up, that's why I use it; but after waking up there is a longish time till all your needed processes really wake up and you can start to work. If you left "top" running somewhere you can observe how the used memory for buffers and cache start to increase rapidly. Also, there is something around 200MiB that remains in swap and is not used again: ie, the process of suspending has "freed" (swapped out) some useful memory. - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFFKh57tTMYHG2NR9URAlpbAKCX0/t3cF4dfEYUTN/mgxnLfvXCSQCgjnbD LqsA4REibr/RYvTIkl43/WQ= =OqAt -----END PGP SIGNATURE-----
Hans, On Sunday 08 October 2006 15:03, Hans Witvliet wrote:
On Fri, 2006-10-06 at 08:16 +0200, Hans du Plooy wrote:
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
Probably i'm missing something... On most systems i encounter, much of the memory is used by buffers or cache.
What's the point of writing that info back to a swap partition, (as it is already somewhere on disk anyhow)
Any data in RAM that is associated with a file block will be, if dirty, written to that disk block before that RAM is reassigned to some other use. If the RAM in question is not dirty (exists already on disk identically to what is in memory), then the existing contents are simply abandoned and the RAM cleared and reassigned to the new use. So if a block of RAM holds a file block, it will not be sent to swap. Swap is used only for RAM contents that are not backed by an existing disk block. That mostly means running program data.
Hans
Randall Schulz
Hans du Plooy
On Fri, 2006-10-06 at 01:57 +0200, Carlos E. R. wrote:
Does the 2gb limit on swap filesystem still apply? Or did I get lost in kernel 2.2 days?
No, I have a 6 GiB swap.
Sorry, I worded my question poorly. I know you can make more than 2GB, I have several servers with 4GB.
What I meant is is the size of a single swap partition still limited to 2GB?
No, it's not.
Reason I'm asking is that I want to get suspend (to ram and to disc) working on my notebook, which has 2GB RAM, so I need at least 2GB swap.
You don't need it that large in most cases since buffers are not saved, so run free to check how large it should really be... Ok, there might be cases where you then cannot suspend but with 2 GB RAM I doubt this will happen, Andreas -- Andreas Jaeger, aj@suse.de, http://www.suse.de/~aj/ SUSE Linux Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GPG fingerprint = 93A3 365E CE47 B889 DF7F FED1 389A 563C C272 A126
participants (10)
-
Alexey Eremenko -
Andreas Jaeger -
Carlos E. R. -
Hans du Plooy -
Hans Witvliet -
James Knott -
Randall R Schulz -
Robert Lewis -
Stan Glasoe -
stephan beal