I have ASP.NET 2.0 applications running on 32 bit Windows 2K3 Standard edition with 4GB of RAM. I want to upgrade the server to Enterprise edition and add more memory to a total of 6GB. I assume that I will need to enable PAE extensions to do this.
How much of this extra 2GB will be usable to the W3WP worker processes? The root issue is that 2 of the WPs are exceeding 900MB every so often and causing OutOfMemory Exceptions.
The alternative is that I get a new server and move half the applications to it, which is a more expensive and time consuming option.
Thanks
In order to use the extra 2GB /PAE must be enabled in the boot.ini. Each WP will then still be limited to 2GB physical memory.
http://support.microsoft.com/kb/283037
http://msexchangeteam.com/archive/2004/08/20/217772.aspx
You will not need the PAE extensions. As long as you don't have a WP that needs more than 2GB of its own.
Related
My system uses a third part kernel built in native libraries (C++) with a J2EE upper layer running on Tomcat 6. The vendor stipulates 32bit JDK and overall the application very memory hungry. We are presently running on Windows x64 with 32 bit JVM. Essentially, the JVM will hang once the Virtual Size gets close to the 2GB 32bit addressing limit.
Question: From time to time, the third party frameworks will make large requests for memory and this pushes up the Virtual Size allocated on the server. The Virtual Size allocated will never recover even though it appears that the memory that the kernel is reducing its memory needs. In a typical Tomcat deployment, does the Virtual Size ever recover automatically or does it always act as a high water level that keeps on rising? Is there a way to tell the JVM to try to lower the Virtual Size dynamically?
I suspect that the 3rd party native kernel is to blame here but I need to investigate all our options.
FYI - AWE in Windows is not a clear option as the vendor does not officially support any JVMs that have AWE support. Migration to Linux is also not an easy path but is being considered.
Imagine the same hardware running Windows XP 32bit, or Windows XP 64bit..
(being that it's a 64bit processor currently running XP 32bit)
2gigs of ram...
Will the performance of Visual Studio benefit from going to the 64bit OS?
The hardware and ram is currently out of my control... If I could throw more hardware or ram at it I would.
For 2 GB of RAM, most likely not. The biggest advantage of 64-bit is the additional address space. With 2GB of physical RAM, 32-bit OS's can map all of physical memory.
Above 3GB 64-bit OS does give some benefit, since some of your physical memory may be unusable on 32-bit OS's due to devices mapping physical addresses for their own use.
And obviously if you want to use above 4 GB of memory you should absolutely go for a 64-bit OS.
Yes, if you have sufficient physical memory, you will gain some benefits from running Visual Studio in 64-bit Windows as described in Visual Studio: Why is there no 64 bit version? (yet):
Doesn’t being a 64 bit application save you all kinds of page faults and
so forth?
A 64 bit address space for the process
isn’t going to help you with page
faults except in maybe indirect ways,
and it will definitely hurt you in
direct ways because your data is
bigger. In contrast a 64 bit
operating system could help you a lot!
If you’re running as a 32 bit app on a
64 bit OS then you get all of the 4G
address space and all of that could be
backed by physical memory (if you have
the RAM) even without you using 64 bit
pointers yourself. You’ll see
potentially huge improvements related
to the size of the disk cache (not in
your address space) and the fact that
your working set won’t need to be
eroded in favor of other processes as
much. Transient components and data
(like C++ compilers and their big .pch
files) stay cached in physical
memory, but not in your address space.
32 bit processes accrue all these benefits just as surely as 64 bit
ones. (my emphasis added)
not unless you add more RAM.
In fact 64 bits might even slow you down because 64-bits Windows sometimes have to load both 32-bits and 64-bits versions of a same DLL in RAM.
Add more RAM is the way to go because if you are using Windows 7 or Vista they aggressively caches disk files in RAM.
i need to run a few visual studios on windows XP and it seems to take up a lot of memory. i am also running resharper which is a memory hog.
i am running 32 bit XP. How much memory can i put into my machine until i get to the point where the OS hits its limit.
Also, any other ways of running multiple visual studio without such slow performance.
32-bit Operating Systems are limited to 4 GB of RAM, which may or may not be enough for you. Also, I think Windows shows 3 GB of RAM if you install 4 GB.
I suggest you switch to 64-bit and upgrade to 8 GB if you can.
UPDATE: See Jeff's blog post on the subject: Dude, Where's My 4 Gigabytes of RAM?
The maximum amount of memory that can be seen by 32bit WinXP is somewhere between 3 and 4 gigabytes depending on your chipset.
I have also run into issues running multiple instances of VS when I had resharper installed. The only thing you can do is run 64bit XP with more memory, or not use resharper (which is a bummer).
32-bit Windows kernel divides the 4GB virtual addressing space in 2GB/2GB partitions. If you feed the /3GB switch to NTLDR it will offer 1GB kernel space / 3GB user mode space. Note that this NOT implies that you can't write software to take advantage of machines with 32-bit CPUs and address more than 4GB at once.
A workaround is the hardware-supported feature to access the remaining memory in banks or "windows" since the CPU still sees a maximum of 4GB addressable space at once. Some database and GIS software offer this possibility. This is called Physical Address Extensions and allows to use (not addressing at once) up to 64GB with 36-bit addresses. WinXP offers AWE, an API built on top of PAE.
That's the theory. For using Visual Studio you can get the full 4GB for your system or upgrade to a 64-bit OS with more RAM. This only if VS offers a 64-bit version.
"Also, any other ways of running multiple visual studio without such slow performance."
+1 trick: you should use a RAM disk (download) to accelerate I/O.
If you're using - and hopefully do - source-managament system (ie. Subversion), you must just checkout your projects there. VS.NET makes tons of I/O calls, and RAM disks are much faster than real disks.
CAUTION! If you turn off your computer, RAM Disk disappers.
From what I understand, a 32-bit process can only access 2 GB of memory on 32-bit Windows without the /3GB switch, and that some of that memory is taken up by the OS for its own diabolical reasons. This seems to mesh with my experience as we have an app that crashes when it reaches around 1.2 - 1.5 GB of RAM without memory exceptions, even though there is still plenty of memory available.
Would moving this 32-bit application to 64-bit Windows allowing it accesses more than 1.5 GB it can now? Would the application itself have to be upgraded to 64-bit?
Newer versions of Visual Studio have a new flag which make 32-bit apps "big address space aware". Basically what it does is say that if it's loaded on a 64-bit version of windows, then it will get 4GB (the limit of 32-bit pointers). This is certainly better than the 2 or 3 GB you get on 32-bit versions of windows. See http://msdn.microsoft.com/en-us/library/aa366778.aspx:
Most notably it says:
Limits on memory and address space
vary by platform, operating system,
and by whether the
IMAGE_FILE_LARGE_ADDRESS_AWARE value
of the LOADED_IMAGE structure and
4-gigabyte tuning (4GT) are in use.
IMAGE_FILE_LARGE_ADDRESS_AWARE is set
or cleared by using the
/LARGEADDRESSAWARE linker option.
Also see: http://msdn.microsoft.com/en-us/library/wz223b1z.aspx
Yes, under the right circumstances, a 32-bit process on Windows can access a full 4GB of memory, rather than the 2Gb it's normally limited to.
For this to work, you need the following:
The app must be running on a 64-bit OS
The app must be compiled with the /LARGEADDRESSAWARE flag.
The app should be tested to make sure it actually works properly in this case. ;) (specifically, code that relies on all pointers pointing to addresses below the 2GB boundary will obviously not work here)
Your app will be limited by the pointer size, in your example 32 bits.
If your app was to access more memory then you would need some sort of segmented memory architecture like we had in the 16 bit days where apps used 16bit pointers and offsets to access the full 32bit memory space.
WOW64 allows using 32-bit Windows application on 64-bit Windows, translating 32-bit pointers to real 64-bit pointers. And actually 32-bit addressing should allow accessing 4GB of memory.
Obviously, that's 64-bit windows.
Also, what's the maximum amount of memory a single 64-bit process can use?
I was kind of counting on using it all...
(Yes, I know what I'm doing, please don't tell me that if I need that much RAM i must be doing something wrong)
Also, is this the same for a .Net 2.0 process? Or is there a lower limit for .Net?
What version of windows? it differs from XP to vista and from home to business versions of vista, and I would guess again for server.
see here for more info on maximum ram for diffrent windows versions
for Windows Server 2008 Datacenter MS quote 2 TB of physical memory.
Link
From http://technet.microsoft.com/en-us/library/cc758523.aspx
- Windows Server 2003, 64 bit Datacenter Edition supports physical memory up to 512GB
A single process should be able to use most of it, some will be used by the OS.
The answer from Re0sless is better then mine. The limit is now 2TB, in Datacenter SP2, and 2008.
We run Windows boxes with 16 gigs of memory, but that is because we are running multiple VM Ware instances, I presume you mean in a single instance. On Vista it depends upon the edition. It breaks out like this:
Vista Basic: 8 GB
Vista Home Premium: 16 GB
Vista Business/Enterprise/Ultimate: 128+ GB
Something we found out recently: with MySQL running on Win32, you can only use up to 2GB per process. On Win64, the memory is not managed as well and a single MySQL instance will run your memory into the ground. Ours used up all 16GB we have. So regarding how much memory 1 64-bit process can use: the answer is however much the OS allows.
According to wikipedia you can have 128 GB of physical RAM in a 64-bit Windows XP computer.
This is a Windows Server machine.
As for which edition (Datacenter, Enterprise, etc)... Whatever it takes to give my little .Net Process as much memory as it can.
Switch to Linux. You will not have any of these issues and you will get better performance.