Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On Friday 23 January 2009 14:58:32 Grant Edwards wrote: Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. In the days when I ran Windows I used to have at least one partition other than C and force the swap file onto it, with fixed size. Then I could just omit that partition from the backup. Perhaps it's still possible to do that; I don't know, but it might be worth a try. -- Rgds Peter
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 23 Jan 2009, at 21:10, Paul Hartman wrote: ... From memory it's just to delete it, which is perfect. It would take too long to zero it out - I don't think that's the purpose. ... After further googling, it appears it *does* fill the pagefile.sys with zeros, and adds a significant delay to windows shutdown times. So it won't do anything for the OP in this case. I don't know why I said from memory before, I was surely just making the assumption. ISTM a bit daft, under Windows, to zero out the pagefile. If you have physical access to the computer, most anything in the swapfile will be available elsewhere on the hard-drive anyway. About the only thing you *might* get out of it is passwords, but that's not something for a very amateur hacker. I guess writing the whole routine to (free up swap memory, check the registry for this setting ) zero the swapfile not to have been a mere 5 minute job. How hard would it have been to add an option _just_ to delete it? This just requires freeing the inode, is surely less work, and would have been more useful to far more people. *sigh* Microsoft. Stroller.
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-24, Peter Humphrey pe...@humphrey.ukfsn.org wrote: On Friday 23 January 2009 14:58:32 Grant Edwards wrote: Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. In the days when I ran Windows I used to have at least one partition other than C and force the swap file onto it, with fixed size. Then I could just omit that partition from the backup. Perhaps it's still possible to do that; I don't know, but it might be worth a try. Yes, it's still possible to do that. I didn't figure out I _should_ do that until it was too late and the disk was partitioned and several OSes installed -- I didn't have a spare primary parition to put the swap file on. I had a bunch of spare extended partitions but all the docs say you can't put the XP swap file on en extended paritition (unless you use something like swapfs, which will work with an extended partition). -- Grant
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On Saturday 24 January 2009 15:35:32 Grant Edwards wrote: I didn't have a spare primary parition to put the swap file on. I had a bunch of spare extended partitions but all the docs say you can't put the XP swap file on en extended paritition... Ah, I didn't know that. In Win98, I think it was, I used to put it on drive E, which was a logical disk in the extended partition. -- Rgds Peter
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-24, Peter Humphrey pe...@humphrey.ukfsn.org wrote: On Saturday 24 January 2009 15:35:32 Grant Edwards wrote: I didn't have a spare primary parition to put the swap file on. I had a bunch of spare extended partitions but all the docs say you can't put the XP swap file on en extended paritition... Ah, I didn't know that. In Win98, I think it was, I used to put it on drive E, which was a logical disk in the extended partition. I didn't actually try it, so maybe I was wrong -- but I swear I read that somewhere (and it sounded like the sort of restriction one would run into under Windows). [some googling] I can't find any confirmation for what I claimed about swap files on logical paritions. I must have mis-read something or conflated it with the restriction that XP itself can't be installed on a logical partition. :/ It looks like I could have created a small logical partition for an NTFS filesystem in which I could have placed the swap file. I still can't believe that Windows does it's swapping using a normal filesystem -- and by default it's the same filesystem used for system and application files. It seems like the filesystem code would end up being a serious bottleneck. But I long ago stopped trying to figure out why Windows does things... -- Grant
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Grant Edwards wrote: I still can't believe that Windows does it's swapping using a normal filesystem -- and by default it's the same filesystem used for system and application files. It seems like the filesystem code would end up being a serious bottleneck. But I long ago stopped trying to figure out why Windows does things... There actually is a good reason (oddly enough) for Windows using a file on the filesystem for its swap space. Because it is a simple file on disk, if Windows realizes that the swap file is almost full, it can expand your swap without having to do things like repartition. This makes the swap is full - out of memory-type problems less likely to occur (unless it is filesystem is full as well :) ). - -- ABCD -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkl7Za8ACgkQOypDUo0oQOp8egCgwWyB4db6ZYJ9YwgvG/dq70Rq 64cAn3laOOtlhh7zN7ni85WpBYZDyLz6 =T1za -END PGP SIGNATURE-
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-24, ABCD en.a...@gmail.com wrote: There actually is a good reason (oddly enough) for Windows using a file on the filesystem for its swap space. Because it is a simple file on disk, if Windows realizes that the swap file is almost full, it can expand your swap without having to do things like repartition. This makes the swap is full - out of memory-type problems less likely to occur While that's a valid point in theory, I've never had a swap is full - out of memory problem in all the years I've been running Unixes that swapped to dedicated partitions. In my experience the system usually slows to a standstill and requires drastic action long before swap fills up. (unless it is filesystem is full as well :) ). That, on the other hand, I do run into quite regularly. So it seems to me that using a swap file rather than a paritition is increasing the liklehood of problems rather than decreasing it while at the same time adding both system overhead and instability. Surely it's easier to corrupt a swapfile that's in a normal, heavily-used filesystem than it is to corrupt a dedicated swap partition? The code that prevents one partition from spilling over into another is much, much simpler and more bullet-proof than the code that manages blocks/clusters within a filesystems. If I were to guess why Windows doesn't use a swap partition, it would be because floppy disks didn't have partitions. -- Grant
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 24 Jan 2009, at 17:22, Grant Edwards wrote: I still can't believe that Windows does it's swapping using a normal filesystem -- and by default it's the same filesystem used for system and application files. It seems like the filesystem code would end up being a serious bottleneck. 3. Does creating the swapfile on a journaled filesystem (e.g. ext3 or reiser) incur a significant performance hit? None at all. The kernel generates a map of swap offset - disk blocks at swapon time and from then on uses that map to perform swap I/O directly against the underlying disk queue, bypassing all caching, metadata and filesystem code. http://lkml.org/lkml/2005/7/7/326 Stroller.
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-24, Stroller strol...@stellar.eclipse.co.uk wrote: 3. Does creating the swapfile on a journaled filesystem (e.g. ext3 or reiser) incur a significant performance hit? None at all. The kernel generates a map of swap offset - disk blocks at swapon time and from then on uses that map to perform swap I/O directly against the underlying disk queue, bypassing all caching, metadata and filesystem code. I supposed that the NT kernel does something similar. One implication of that is that the filesystem is then not allowed to move blocks around if they are part of an active swap file? Not that I'm aware of filesystems that shuffle blocks around while they're part of an open file, but one might imagine something like that happening as part of some sort of balancing algorithm. -- Grant
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Grant Edwards wrote: One implication of that is that the filesystem is then not allowed to move blocks around if they are part of an active swap file? Not that I'm aware of filesystems that shuffle blocks around while they're part of an open file, but one might imagine something like that happening as part of some sort of balancing algorithm. I'm not sure if the swap can be moved around during normal use, but I do know that it shows up as an unmovable block in XP's defragmentation tool, suggesting that nothing is allowed to move it on disk at all, while it is in use (which, on Windows, means the OS is running). - -- ABCD -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkl70wsACgkQOypDUo0oQOqDPgCfc78Ejvm96lonhVA581xCftXu c9UAoL+YzrNHQ8iJL+fCmAUlD5WG9s5w =KeKc -END PGP SIGNATURE-
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 05:16, Grant Edwards wrote: ... I found a very slick solution that lets Windows XP use a Linux swap partition for swap/paging/vm/whatever-MS-calls-it: http://db.bme.hu/~surprof/SwapFs-i/ That looks a really cool useful idea. However, I have a reservation. Since you NEED to use it - perhaps for space considerations? Yup. Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. - the go for it, by all means. But if this driver is slower at reads or writes than Windows' own NTFS driver then it may actually slow the computer down. Could be. My understanding is that the system is still using the Windows NTFS driver. I believe that swapfs is a block-device filter driver that sits between the NTFS driver and the bottom layer block device driver (the IDE driver or the SATA driver or the SCSI driver). In the case of a driver written by an individual, who is likely not as familiar with Windows' APIs, or who may not be able to use the private APIs used by Windows' own filesystem drivers, I find it quite possible the performance may be questioned. Well, there are several individuals who've worked on it. That said, I can't swear that there aren't performance implications. There probably are, since it adds a layer between the SATA driver (in my case) and the NTFS driver. But, I haven't noticed any visible slow-down, and the machine is more than fast enough for my purposes. Besides, if you're running MS Windows, you've already lost the war when it comes to swapping performance: anybody who cares about swap performance wouldn't be using a normal file on a normal filesystem for it... Someday when I'm bored, maybe I'll google for a file I/O benchmark for windows and run it with and without the swapfs layer. -- Grant Edwards grante Yow! INSIDE, I have the at same personality disorder visi.comas LUCY RICARDO!!
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 23 Jan 2009, at 14:58, Grant Edwards wrote: On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 05:16, Grant Edwards wrote: ... I found a very slick solution that lets Windows XP use a Linux swap partition for swap/paging/vm/whatever-MS-calls-it: http://db.bme.hu/~surprof/SwapFs-i/ That looks a really cool useful idea. However, I have a reservation. Since you NEED to use it - perhaps for space considerations? Yup. Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. It might be possible to script removing the swap file at shutdown (or place a wrapper script to mount the partition remove the swapfile before running ntfsclone). But I appreciate this is less elegant than just using the same swap partition for both o/s. Stroller.
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 14:58, Grant Edwards wrote: On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 05:16, Grant Edwards wrote: ... I found a very slick solution that lets Windows XP use a Linux swap partition for swap/paging/vm/whatever-MS-calls-it: http://db.bme.hu/~surprof/SwapFs-i/ That looks a really cool useful idea. However, I have a reservation. Since you NEED to use it - perhaps for space considerations? Yup. Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. It might be possible to script removing the swap file at shutdown (or place a wrapper script to mount the partition remove the swapfile before running ntfsclone). I thought about that. It probably would be a bit more robust than using the Linux swap partition, but it seemed too much like giving in to Microsoft. :) But I appreciate this is less elegant than just using the same swap partition for both o/s. -- Grant Edwards grante Yow! Everybody is going at somewhere!! It's probably visi.coma garage sale or a disaster Movie!!
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On Fri, Jan 23, 2009 at 10:08 AM, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 14:58, Grant Edwards wrote: On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 05:16, Grant Edwards wrote: ... I found a very slick solution that lets Windows XP use a Linux swap partition for swap/paging/vm/whatever-MS-calls-it: http://db.bme.hu/~surprof/SwapFs-i/ That looks a really cool useful idea. However, I have a reservation. Since you NEED to use it - perhaps for space considerations? Yup. Mainly because I use ntfsclone to keep a bunch of backup copies of the NTFS partition, and having a 2GB swap file in every backup copy starts to eat up a lot of disk space. It might be possible to script removing the swap file at shutdown (or place a wrapper script to mount the partition remove the swapfile before running ntfsclone). But I appreciate this is less elegant than just using the same swap partition for both o/s. http://support.microsoft.com/kb/314834 There is a registry setting in Windows to clear the pagefile.sys at shutdown. What does clear mean? To overwrite with 0? To delete? I don't know. Paul
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 23 Jan 2009, at 17:09, Paul Hartman wrote: ... http://support.microsoft.com/kb/314834 There is a registry setting in Windows to clear the pagefile.sys at shutdown. What does clear mean? To overwrite with 0? To delete? I don't know. From memory it's just to delete it, which is perfect. It would take too long to zero it out - I don't think that's the purpose. Instead, I think, it should prevent swapfile fragmentation - making it a very good general-purpose setting to enable. What would be really idea for the OP is some kind of grub setting a bash script that formats the partition to the appropriate format for the o/s being booted. But you'd have to be clever about it to avoid long boot times. Stroller.
Re: [gentoo-user] Re: Howto share Linux swap partition with Windows XP
On Fri, Jan 23, 2009 at 2:53 PM, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 17:09, Paul Hartman wrote: ... http://support.microsoft.com/kb/314834 There is a registry setting in Windows to clear the pagefile.sys at shutdown. What does clear mean? To overwrite with 0? To delete? I don't know. From memory it's just to delete it, which is perfect. It would take too long to zero it out - I don't think that's the purpose. Instead, I think, it should prevent swapfile fragmentation - making it a very good general-purpose setting to enable. What would be really idea for the OP is some kind of grub setting a bash script that formats the partition to the appropriate format for the o/s being booted. But you'd have to be clever about it to avoid long boot times. Stroller. After further googling, it appears it *does* fill the pagefile.sys with zeros, and adds a significant delay to windows shutdown times. So it won't do anything for the OP in this case.
[gentoo-user] Re: Howto share Linux swap partition with Windows XP
On 2009-01-23, Stroller strol...@stellar.eclipse.co.uk wrote: On 23 Jan 2009, at 17:09, Paul Hartman wrote: ... http://support.microsoft.com/kb/314834 There is a registry setting in Windows to clear the pagefile.sys at shutdown. What does clear mean? To overwrite with 0? To delete? I don't know. From memory it's just to delete it, which is perfect. That would eliminate the issue of a backup snapshot having 2GB of pagefile.sys and 1.7GB of other stuff. It would take too long to zero it out - I don't think that's the purpose. Instead, I think, it should prevent swapfile fragmentation - making it a very good general-purpose setting to enable. What would be really idea for the OP is some kind of grub setting a bash script that formats the partition to the appropriate format for the o/s being booted. But you'd have to be clever about it to avoid long boot times. I found some old postings from 6-8 years ago from people who were trying to do that. Nobody seemed to have come up with anything that worked very well. Since then disks have gotten large enough that normal people don't care about a few GB. -- Grant Edwards grante Yow! I have many CHARTS at and DIAGRAMS.. visi.com
