BitLocker - why 1500 MB partition?

[Anders Lund]

Hi

Running Windows Vista x64 SP2 beta on a HP notebook.

I use BitLocker and have no problems with it. But I have yet to
discover the reason for the BitLocker drive have to bee (at least?)
1500 MB in size. Looking at the properties for the drive, I can see
that only about 50 MB is in use.

Reasons I have thought of could be:
- Windows Vista have to have at least 1500 MB on the boot partition
(for some reason).
- Windows need to have room to save some dump files to a non-encrypted
drive.
- In case of the need of Windows Repair, it must have room to save
files on a non-encrypted drive.

These are all unconfirmed theories. So I ask you - What is up with the
1500 MB partition?

/Anders

 

[Darrell Gorter[MSFT]]

Hello Anders,
It's required to allow for backup of the volume.
If the volume size is too small backup cannot take place on that volume,
this would prevent those volumes from being backed up or restored
Thanks,
Darrell Gorter[MSFT]

This posting is provided "AS IS" with no warranties, and confers no rights
--------------------
| >From: Anders Lund <[email protected]>
| >Newsgroups: microsoft.public.windows.vista.security
| >Subject: BitLocker - why 1500 MB partition?
| >Date: Wed, 10 Dec 2008 00:49:02 -0800 (PST)
| >Organization: http://groups.google.com
| >Lines: 21
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| >NNTP-Posting-Date: Wed, 10 Dec 2008 08:49:02 +0000 (UTC)
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| >Xref: TK2MSFTNGHUB02.phx.gbl
microsoft.public.windows.vista.security:19983
| >X-Tomcat-NG: microsoft.public.windows.vista.security
| >
| >Hi
| >
| >Running Windows Vista x64 SP2 beta on a HP notebook.
| >
| >I use BitLocker and have no problems with it. But I have yet to
| >discover the reason for the BitLocker drive have to bee (at least?)
| >1500 MB in size. Looking at the properties for the drive, I can see
| >that only about 50 MB is in use.
| >
| >Reasons I have thought of could be:
| >- Windows Vista have to have at least 1500 MB on the boot partition
| >(for some reason).
| >- Windows need to have room to save some dump files to a non-encrypted
| >drive.
| >- In case of the need of Windows Repair, it must have room to save
| >files on a non-encrypted drive.
| >
| >These are all unconfirmed theories. So I ask you - What is up with the
| >1500 MB partition?
| >
| >/Anders
| >

 

[Paul Adare]

Hello Anders,
It's required to allow for backup of the volume.
If the volume size is too small backup cannot take place on that volume,
this would prevent those volumes from being backed up or restored

That's not the original reason given. Nor does that explain why in Win7 the
partition is only 200 MB. The original reason given was that certain
servicing operations, such as patching Office required a certain amount of
free space on the system volume.

 

[Darrell Gorter[MSFT]]

Hello Paul,
Not sure what the reason you heard was.
There may be other requirements as well.
There was a limit in VSS, so Complete PC Backup would not backup the volume
unless the size was at least one gig.
See this technet article
http://technet.microsoft.com/en-us/library/bb808827.aspx
Also, the volume must be at least 1 gigabyte (GB) for DPM to protect it.
DPM uses the Volume Shadow Copy Service (VSS) to create a snapshot of the
protected data, and VSS will create a snapshot only if the volume size is
greater than or equal to 1 GB.

There was also an requirement for the volume to have at least 400 meg free
in order to be able to upgrade from edition to edition (Home to Ultimate)
or from a downlevel OS.
Certain setup files as well as the WinPE (boot.wim) file were copied to
that volume to loaded on the subsequent reboot.



Thanks,
Darrell Gorter[MSFT]

This posting is provided "AS IS" with no warranties, and confers no rights
--------------------
| >From: Paul Adare <[email protected]>
| >Subject: Re: BitLocker - why 1500 MB partition?
| >User-Agent: 40tude_Dialog/2.0.15.1
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| >Content-Type: text/plain; charset="us-ascii"
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| >Reply-To: (e-mail address removed)
| >Organization: IdentIT In.c
| >References:
<50367e0c-0be8-4c3d-998f-db8eca9416b7@a26g2000prf.googlegroups.com>
<[email protected]>
| >Date: Wed, 10 Dec 2008 21:52:03 -0600
| >Message-ID: <[email protected]>
| >Newsgroups: microsoft.public.windows.vista.security
| >NNTP-Posting-Host: 12.41.223.154
| >Lines: 1
| >Path: TK2MSFTNGHUB02.phx.gbl!TK2MSFTNGP01.phx.gbl!TK2MSFTNGP04.phx.gbl
| >Xref: TK2MSFTNGHUB02.phx.gbl
microsoft.public.windows.vista.security:20014
| >X-Tomcat-NG: microsoft.public.windows.vista.security
| >
| >On Thu, 11 Dec 2008 03:32:20 GMT, "Darrell Gorter[MSFT]" wrote:
| >
| >> Hello Anders,
| >> It's required to allow for backup of the volume.
| >> If the volume size is too small backup cannot take place on that
volume,
| >> this would prevent those volumes from being backed up or restored
| >
| >That's not the original reason given. Nor does that explain why in Win7
the
| >partition is only 200 MB. The original reason given was that certain
| >servicing operations, such as patching Office required a certain amount
of
| >free space on the system volume.
| >
| >--
| >Paul Adare
| >MVP - Identity Lifecycle Manager
| >http://www.identit.ca
| >

 

[Anders Lund]

Hello Paul,

Thank you both for your input.

/Anders