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What is the recommended size for a server 2008 system partition? I've seen 20GB as well as 49GB suggested but I can't seem to find any white papers or best-practices documents on the subject.

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12 Answers 12

up vote 9 down vote accepted

It depends... According to the official system requirements (http://www.microsoft.com/windowsserver2008/en/us/system-requirements.aspx) 32-bit installs of the OS need at least 20GB, while 64-bit installs require at least 32 GB. The OS itself takes up about 10GB if I recall correctly, but you need to factor in:

  • Page file (typically 1.5x your physical RAM)
  • Over 15% free space so that you can defrag
  • Space for any applications you may install
  • Space for the dump file (1x your physical RAM)
  • Space for log files

With hard drives being as cheap as they are these days, I would recommend not skimping on space for the OS partition. Give yourself some extra room for things you forgot to factor in... it is much easier to allocate the space up front than it is to make space a year from now.

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+1 I ended up picking 175gb system, 360gb VHD partition on my raid10 DAS. The way I see it, if I ever come to a point that I feel this needs rebalanced I can just shrink C: again if I need to. If I can't shrink C: then, that means clearly I made the right choice upfront and just need a separate disk store. –  Chris Marisic Mar 16 '11 at 14:26
    
might want to factor in a growing Windows\winsxs folder, I have one that is about 10GB on a system I am working on right now. blogs.technet.com/b/askcore/archive/2008/09/17/… –  RandyMorris Aug 18 '11 at 2:11
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Disagreed, SAN is expensive... –  CMag Dec 16 '11 at 17:39

As far as cleaning up the Winsxs directory... don't. You will break future updates, MSIs, and Windows Update from working.

See more here: http://blogs.msdn.com/jonwis/archive/2007/01/02/deleting-from-the-winsxs-directory.aspx

Even better... from the Windows 7 Engineering team, everything you need to know about Microsoft's engineering goals around disk space and the real size of the sxs folder (it's not as big as you think):

http://blogs.msdn.com/e7/archive/2008/11/19/disk-space.aspx

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thanks for pointing similar question. –  pQd Jun 5 '09 at 7:49

You need to account for software installations and any additional space those applications may also take up. Some software apps will only allow writing their data or caching files to the c:\ drive, so using anything less than 100GB is a huge mistake you will only make once. Proper planning avoids reinstallation.

Most new software apps on the market are bloatware. Allow for this.

Drive space is cheap, go 250GB. Better to have it and not to need it.

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Beware c:\windows\winsxs. This folder will infinately grow with "hardlinked" copies of system dll's. On a windows server 2008 64bit server we have running for approximately 1 year, this folder is 11GB in size. There was a recommendation of 100GB, I would highly agree with this recomendation. Plan for the future. :)

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A real problem in previous versions of Windows was it was difficult to extend the size of the system partition, you needed to use third party tools which were a little dicey.

However, with 2008 they've included the ability to expand and shrink partitions, including the C: drive.

This means if you get it wrong to start with, you can probably rectify the issue reasonably easily. If you were using 2003, you'd be a right pickle.

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Also just noticed that the HP SmartStart CD tool came up with the following error when trying to install Windows 2008 64 Bit on a 36GB system disk: Boot drive size (34727 MB) is smaller then the minimum recommended 45056MB I guess HP knows best. Interesting point to reiterate as well, 64 Bit 2008 uses up more disk space then the 32 Bit version does. –  SteveBurkett Jun 19 '09 at 11:01

Don't mess around 100gb is standard on 2008 server if you want a comfortable life If you go less than 60 on the new installs I wi not allow you to proceed these days

So C:\ = 100gb no less

Trust me.

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To be honest, I can't imagine installing a Windows server with less than 40Gb as a bare minimum, ideally 60Gb or even 80Gb for the system partition.

As for WinSXS cleanup, you'll find a lot of people claiming you can do this and that, and Microsoft telling you to leave it alone apart from maybe one or two very specific issues. On a workstation I might be persuaded to experiment but on a server I'd be wary about betting against the vendor's suggestions.

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right. 40gb for the system and... raid-0 instead of raid-1 on 37gb hard drives. just kidding. –  pQd Jun 5 '09 at 7:51

2008 also adds hibernate, so there´s a hibernate file aswell (equals ram size)

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Why on earth would you ever hibernate a server? Perhaps this should be a question on its own? –  Jon Rhoades Jun 18 '09 at 13:53
    
some of us web developers use server 2008 as our main OS. –  Nathan DeWitt Jun 18 '09 at 13:57
    
@Jon We should ask MS for that... –  lepole Jun 20 '09 at 20:47
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Opening a command prompt as Administrator and issuing a 'powercfg /hibernate off' will get rid of the hibernate file (which as Lepole says, can be a good 8GB or so these days). Probably good practice in virtualisation farms if you're trying to keep your disk requirements on your SAN down. –  SteveBurkett Jun 3 '10 at 13:35

I've got a bunch of VMs. I started them at 20 Gigs. Some I've had to increase to 25, others to 30. Others are fine with 20 Gigs.

All apps I install on D, so I've got OSs only on C. For my physical machines I've got 50 Gig C Drives setup.

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I went with 40gb - I'm pretty comfortable with the 15gb free it's settled into.

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If you attempt to install 2008 on a partition less than 40GB, the setup process will spew a bunch of stuff onto some other larger partition, and it's a bitch to remove later on.

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I used to go with 20GB system partition but that has bitten me on more than one occasion. I now use 60GB as my "default" system partition unless there is a need to go bigger.

Believe me it is always easier to do things right up front then have to re-do them later.

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