Using HORM, with a pagefile

[psucro]

Is there a way to use HORM (Hibernate, Once Resume Many) with EWF
(Enhanced Write filter) on a partition which uses a pagefile, (the
pagefile resides on another unprotected partition.)

--> I'm looking for quicker bootup time, by using HORM.

Basically, HORM stores the snapshot of system memory, when the
hibernation file is created.
--> So the pagefile must match this current state of memory.
--> So if the pagefile which is on the unprotected partition
changes, and you use a state of memory when the pagefile was
different, you can have corruption problems.

Reading other's documentation talks about unmounting all drives which
are not protected by the write filter.
But, you CANNOT dismount a drive, which contains a pagefile. (Unless
there is some hidden windows function to stop the usage of the
pagefile.)

I can see a number of methods which could be used.

1. Force the pagefile to zero, and flush it so it starts with no
pagefile.
Save the hibernation file at this time.
--> I have not figured out how to set the pagefile to zero length,
without causing a reboot.

2. Somehow start with a base pagefile, which become the current
pagefile on every bootup.
So, the system starts with the hibernation file, and the matching
pagefile on every boot.
--> Maybe, using the runonce registry entry one could copy the
base pagefile, (the once which matches the hibernation file) to the
real pagefile.

3. Maybe create a system which has a starting pagefile which is zero,
but can be expanded. Then somehow don't allow the pagefile to be used,
so the hibernation file can be created with a zero length file.
--> This method will probably fail since, subsequent savings of the
hibernation file, will probably result in a pagefile which was used.

Any other ideas, or solutions would be greatly appreciated.

My system has 3 partitions where only the first partition is protected
with a RAM-REG write filter. The pagefile is located on the 3rd
partition.

I've asked this question years ago, and still have not seen any
answers.

Thanks in advance.
Paul.

 

[mike_moini]

Is there a way to use HORM (Hibernate, Once Resume Many) with EWF
(Enhanced Write filter) on a partition which uses a pagefile, (the
pagefile resides on another unprotected partition.)

--> I'm looking for quicker bootup time, by using HORM.

Basically, HORM stores the snapshot of system memory, when the
hibernation file is created.
  --> So the pagefile must match this current state of memory.
  --> So if the pagefile which is on the unprotected partition
changes, and you use a state of memory when the pagefile was
different, you can have corruption problems.

Reading other's documentation talks about unmounting all drives which
are not protected by the write filter.
But, you CANNOT dismount a drive, which contains a pagefile. (Unless
there is some hidden windows function to stop the usage of the
pagefile.)

I can see a number of methods which could be used.

1. Force the pagefile to zero, and flush it so it starts with no
pagefile.
    Save the hibernation file at this time.
    --> I have not figured out how to set the pagefile to zero length,
without causing a reboot.

2. Somehow start with a base pagefile, which become the current
pagefile on every bootup.
    So, the system starts with the hibernation file, and the matching
pagefile on every boot.
    --> Maybe, using the runonce registry entry one could copy the
base pagefile, (the once which matches the hibernation file) to the
real pagefile.

3. Maybe create a system which has a starting pagefile which is zero,
but can be expanded. Then somehow don't allow the pagefile to be used,
so the hibernation file can be created with a zero length file.
   --> This method will probably fail since, subsequent savings of the
hibernation file, will probably result in a pagefile which was used.

Any other ideas, or solutions would be greatly appreciated.

My system has 3 partitions where only the first partition is protected
with a RAM-REG write filter. The pagefile is located on the 3rd
partition.

I've asked this question years ago, and still have not seen any
answers.

Thanks in advance.
Paul.

HORM does not work w/ pagefile.



If you setup a paging file on a separate partition, that partition
would need to be protected; all partitions in a HORM system must be
protected via EWF-RAM. This is necessary for system state coherency.



There is one exception to this if you could live "unmount" a page
file: http://msdn.microsoft.com/en-us/library/aa940916.aspx.



But using EWF-RAM to protect a paging file is very undesirable because
it defeats any value in using a paging file. EWF backs disk writes to
memory, which defeats the entire intent of a paging file (whose
purpose is to virtualize RAM to a disk file).



Actually HORM is the very fastest means of booting, assuming your
storage I/O path is reasonably fast, because it restores the entire
system memory in one fell swoop and then only the hardware devices
need to be enumerated before the system is running again.



To expediate booting you could also look init minizing the number of
your devices (especially pnp ones), use fast hardware (CPU) and
smaller RAM (which will result in smaller hibernation file).



Hope this helps

Mike