PageFile and Disk Usage

[MadMike261]

I am running without pagefile for ages and ages.
Probably since back in '08 or something when I got 4 gigs of ram for the first time (xp x64).

But now that I am running WCG I am wondering if it needs to be on or off?
Does WCG use it a lot? Or can I perfectly run without?

Currently only running my signature rig. The 4 gig rig went to a relative.

Besides that I am wondering what WCG does when it writes to disk...
You can change this option, but I have no clue what it does at those intervals and what would be the effects of increasing that timer.

Any one that could shed a light on this? I would like to spare my Velociraptors as much as I can
Much appreciated

[Otis11]

I am running without pagefile for ages and ages.
Probably since back in '08 or something when I got 4 gigs of ram for the first time (xp x64).

But now that I am running WCG I am wondering if it needs to be on or off?
Does WCG use it a lot? Or can I perfectly run without?

Currently only running my signature rig. The 4 gig rig went to a relative.

Besides that I am wondering what WCG does when it writes to disk...
You can change this option, but I have no clue what it does at those intervals and what would be the effects of increasing that timer.

Any one that could shed a light on this? I would like to spare my Velociraptors as much as I can
Much appreciated

I don't know how turning off pagefiles is going to affect it, but since you have 8GB of ram I wouldn't think mem would be an issue unless you other applications are memory intensive...(but on the other hand, wouldn't hurt to turn it on. The system won't use it unless it's needed as RAM is much faster)

And the write back time just sets the minimum time that must elapse between checkpoints that it saves to the disk. If you make this number larger it won't save your results as often, but for those with a stable machine who don't turn it off, increasing that number won't make a difference.

Good chance I'm out of my mind right now though, so someone correct me if I'm wrong.

[Sparky]

Well if there is a pagefile available, Windows will stick SOMETHING in it. Why, I don't know. I have a laptop here, fresh load of Windows, 4GB RAM, and it still insists on using 150MB of pagefile even though there is over 3GB of RAM available Just how it is.

[joshd]

Well if there is a pagefile available, Windows will stick SOMETHING in it. Why, I don't know. I have a laptop here, fresh load of Windows, 4GB RAM, and it still insists on using 150MB of pagefile even though there is over 3GB of RAM available Just how it is.

I believe it keeps some stuff in both the ram and the page, so if the ram is needed by a large application it can simply drop the allocated memory with no copy back to disk required?

[Tom128]

I've not used a pagefile in years, crunched without one the entire time.

[sparkler]

ive got 12gb ram and it still uses the pagefile and i need to use a pagefile as 64bit windows filesystem cache is broken

10:39:49 on 6 Apr 2011
Pagefile: E:\pagefile.sys
InitialSize: Not specified
MaximumSize: Not specified
Current Pagefile Usage: 144 MB
Session Peak Usage: 371 MB
Current Pagefile Size: 4096 MB

[Johnmark]

ive got 12gb ram and it still uses the pagefile and i need to use a pagefile as 64bit windows filesystem cache is broken

10:39:49 on 6 Apr 2011
Pagefile: E:\pagefile.sys
InitialSize: Not specified
MaximumSize: Not specified
Current Pagefile Usage: 144 MB
Session Peak Usage: 371 MB
Current Pagefile Size: 4096 MB

What do you mean x64 (Win7) filesystem cache is broken? Just curious as I've not heard this before.
What is the pagefile information you posted from ?

[sparkler]

pagefile info is from PageFileUsageMonitor and filesystem cache is broken as its setup to use all available ram e.g 1073741824KB no matter how much ram you use so it can end up using all your ram for cache which then makes the os think its out of ram so it ends up paging the memory being used by applications/services so then you have 2-3k pagefile usage instead of windows taking the ram used by the cache when it needs it

[D_A]

That's not what would be considered "broken", in fact it's very deliberate on Microsoft's part. Pretty much every memory management feature in Windows is designed to enhance the "desktop experience" and the expense of other applications. They do this because they consider their "customers" sufficiently stupid as to think that if the desktop is fast then the system is fast and all those other applications (ie non Microsoft) must be what is slowing the system down.
It's not a fault, it's a feature ... just for THEIR benefit not yours.

[joshd]

pagefile info is from PageFileUsageMonitor and filesystem cache is broken as its setup to use all available ram e.g 1073741824KB no matter how much ram you use so it can end up using all your ram for cache which then makes the os think its out of ram so it ends up paging the memory being used by applications/services so then you have 2-3k pagefile usage instead of windows taking the ram used by the cache when it needs it

No, the OS is well aware what ram is being used for cache, so if a program demands memory, the OS can simply drop the cache. No paging back to disk needed.

It fills ALL your avaliable ram with cached data that it thinks you are likely to use in the near future. After windows has been installed for a few weeks, its pretty clear that you only use the same few things most of the time, so these things are cached.

EDIT: D_A, its most definitely a feature on a desktop setup, and is only ever a good thing. There is no performance hit by having it enabled, other than a bit of background disk IO required to cache the stuff in the first place.

You could argue that it would be bad to have superfetch enabled on a server, and indeed, it is disabled on MSs server OSes.

[D_A]

It also caches the loaders for every other installed Microsoft application whether you use them or not.

[joshd]

It also caches the loaders for every other installed Microsoft application whether you use them or not.

I've not heard this before, got any links?

Does it not just sort out what you are going to use over a few weeks/months of use? Obviously with a fresh install it might as well just cache what it has installed at the time :/

[D_A]

Links, no, but then MS have never hidden the fact. It's in their interest for their apps to load faster, or at least appear to, than everyone else's after all. Just go through the loaded processes in the System Monitor and you'll find hooks for pretty much every installed MS app as well while other stuff gets to load from scratch.

[sparkler]

No, the OS is well aware what ram is being used for cache, so if a program demands memory, the OS can simply drop the cache. No paging back to disk needed.

It fills ALL your avaliable ram with cached data that it thinks you are likely to use in the near future. After windows has been installed for a few weeks, its pretty clear that you only use the same few things most of the time, so these things are cached.

EDIT: D_A, its most definitely a feature on a desktop setup, and is only ever a good thing. There is no performance hit by having it enabled, other than a bit of background disk IO required to cache the stuff in the first place.

You could argue that it would be bad to have superfetch enabled on a server, and indeed, it is disabled on MSs server OSes.

im not talking about superfetch im talking about filesystem cache superfetch doesn't caused data to be swapped to disk filesystem cache does download this http://technet.microsoft.com/en-us/s...rnals/bb897561 you will see that it and the cached data shown in taskmanager are showing different numbers as there 2 different things

[D_A]

EDIT: D_A, its most definitely a feature on a desktop setup, and is only ever a good thing. There is no performance hit by having it enabled, other than a bit of background disk IO required to cache the stuff in the first place.

You could argue that it would be bad to have superfetch enabled on a server, and indeed, it is disabled on MSs server OSes.

It's not a "bit of background disk IO", it's loading your entire installed RAM with crap. It slows down boot times as well as application load times ... at least non-Microsoft application load times.
It's a bad thing on any system with high disk IO, like a cruncher running CEP2 work units, or anything else with high memory usage as a big chunk of the crap it loads has to be swapped out before the data you actually want can be loaded in. This forces the system to do, minimum, twice the disk access. Given that disk IO is still the biggest bottleneck to system performance this is a really bad thing.

[joshd]

a big chunk of the crap it loads has to be swapped out before the data you actually want can be loaded in.

No, its cache, it can simply drop the data without swapping it.

I suppose if you have high disk IO it could be bad, hence why the server OSes don't have it enabled? Windows desktop OSes are designed for exactly that, high disk IO is not a typical feature.

[D_A]

Whether it's dropped entirely, swapped out or dropped and reloaded when there's "spare" room will depend on the priority of the cached items. High disk IO is typical every time the system is started as well as every time anything of any decent size is loaded. How often disk IO is tasked will vary between workloads, but there is always some time when every system is stuck waiting for disk IO.

[joshd]

I suppose so. Isn't the whole idea with superfetch that you cache stuff while the disk is not being used much, so you don't have to grab from the disk later when it might be under heavy use and then the user asks for a large application? I don't know really, I have no idea how this actually works "under the hood" :P

OP: I guess on a crunching rig there is no reason to have superfetch on, and if you aren't filling the ram there is no reason to have the pagefile on either.

[D_A]

Some apps like to load data into the page file whether it's needed or not. I suspect CEP2 is one of those but I'm not sure. That app does more disk IO than I've ever seen before in crunching.