? Re: Pagefile In Multi-Boot Scenario

Ex_Brit

If you're going through hell, keep going.
Staff member
#1
Guys I need some advice and please...in simple terms.

I have 2 non-raid hard drives each partitioned into 2 - with 4 64-bit OS's on them. (All Ultimate version and fully up to date).

Disk 0: C: Vista, D: Vista (test rig), Disk 1: L: Win 7 M: Win 7 (test rig)

On those test rigs I am more often than not only testing McAfee beta products. D: crashed with a BSOD a couple of times recently and McAfee asked me to submit the crash dump. I would have been only too glad to oblige except there was no crash dump (yes I had system and hidden files exposed).
I've tried it with both kernel dump and minidump, neither are created.

Not being too technical I am a bit limited on my understanding of this but I gather from Googling this that, in order for a crash dump to be created, there has to be a Pagefile on that actual drive and as far as I can see the only pagefile in my system is on C:. Well, according to Diskeeper 2009 that seems to be the case. I also thought that this was normal.

Should I start messing around creating pagefiles on all 4 of them? I thought that the system liked to only have one pagefile.

Addendum:

OK, answering my own question. I realised what to do. Windows apparently by default sets C:\Pagefile.sys as the only pagefile for all drives, so I have now set each drive to a system managed size on each drive.

Hopefully that will cure the lack of dump files.
 
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Terry60

Knows where his towel is.
Staff member
#2
The Install creates a pagefile on the same disk as the Windows folder by default Peter.
When you look in Disk Management though, you won't see the other 3 (inactive) ones, just the active one on the booted system ("boot" "page file").
When you boot any of the other 3 systems, you should see those 2 flags appear on the booted system, and disappear on the previously booted OS.
You can of course, change that default after installation, and it's good for performance if systems on disk 0 use a pagefile on disk1 and v.v..
But the pagefile is only a temporary cache for the dump (convenient in an emergency because it's already open). It will subsequently, on reboot, be copied to a destination defined in your "system" "advanced" parameters.
Have a read of this for details.
 

Ex_Brit

If you're going through hell, keep going.
Staff member
#3
Thanks Terry, I'll keep that reference handy. There def. were no pagefiles on the other 3 drives - I checked each one individually. Now there are. See the pic below. I'm in L: right now but the shaded option was checked in all 4 systems before and I think this was a problem. I guess that was the default setting yet there was only a pagefile on C:.
 

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Terry60

Knows where his towel is.
Staff member
#4
It doesn't show the pagefiles on the other systems from the booted system, unless you've allocated one there to be active from the booted system.
If you booted one of the other systems though, the same picture would emerge. Its C: would be "boot" "page" and a pagefile.sys would show on C: but not on the system you just left.
I'm not quite sure if its "super-hidden" or whether it's allocated dynamically at boot, and therefore ceases to exist between boots, but setting one on W7 from Vista, will result in a clash when you boot W7, where it will say "already exists - shall I overwrite ?"

I've played around with this in the past, manually allocating the page on all my Windows to use the same pagefile (on a separate partition from all of them), and once you get past the delete and replace with its own (identical) version of the empty space, they're all perfectly happy to keep using the same one. (and it stays allocated and visible - making me think that the dynamically added at boot scenario is most likely for the system default)
At the moment, because of multiple W7 installs and a hardware shuffle, I'm back with the default where each system is defaulting to using its own drive and thinks no others exist.
 
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Ex_Brit

If you're going through hell, keep going.
Staff member
#5
Yes, I know one can only see the pagefile in the system one is booted to.
When I was signed into D: (which was the partition I was hoping I'd get a dump file for) there not only was no dump file but there was also no pagefile present. Not according to Diskeeper anyway.
C: was the only pagefile I found on the entire system. Now that I've unchecked that aforementioned option & opted for a system-managed PF on each, I have a pagefile on all of the 4 systems.

Ergo I should now get dump files in the event of a crash.
 

Terry60

Knows where his towel is.
Staff member
#6
Ignore me. I'm talking rubbish.
Conclusions drawn from the evidence in front of me, but based on a false memory of how my systems were configured.
Turns out my Vista and XP systems still use my custom pagefile on the data partition. That's the only reason I can't see pagefiles on Vista and XP from W7. I got rid of them.
In my researches though, I've found one disconcerting fact.
Setting up a pagefile on another HDD for performance (no head contention between paging and other system access) means that you can't get core dumps !
Although the system gives you full control over where you put paging, it doesn't warn you when you do so, that the core-dump facility only works when pagefile is in the same partition root as the OS !
 

Ex_Brit

If you're going through hell, keep going.
Staff member
#7
Terry, why should I ignore you, you are making sense, I was just pointing out things the way they happened here!
Yes, there isn't any warning from Windows and perhaps there should be.