WHS Hard Drive Configuration

DanielT used Ask the Experts™
I am reasonably familiar with WHS (2008) but would like to try and clarify something regarding (internal) hard drives.

My current system is in need of a system drive replacement very soon. I have read that it is best to use the "largest drive you can afford" (up to 2TB, I believe) but also know that the WHS reinstall process will partition the system drive into two (I think) parts being 20GB for the O/S and the remaining as a Data drive. Hopefully all this is correct so far.

My problem? I also understand that WHS will use the DATA partition to maintain its management of files and that - in a multi drive system it will place user data and backups on 2nd, 3rd (etc) drives. SO - why purchase a large drive as a system drive? If  WHS tries to push data to subsequent HDDs as it stores and manages the info, having a large system drive such as 2TB would not be desirable but would seemto be better, instead, as added storage and not as a system drive.

Bottom line...
Should I install a 500GB HDD or push it and go for a 2TB HDD?
I do not want to be in a position of reinstalling the O/S next time for a replacement system disk and lose data.
(ps the current system config is 500GB (sys) + 2000GB (userdata) + 2000GB (userdata) - internal HDDs)

Hope this makes enough sense to someone!

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DarinTCHSenior CyberSecurity Engineer

the difference is physical and logical HDD

a physical HD can be 'broken down' or partition into many logival drives
20GB is the minimum I would use for the system drive 'C:\'
I might encourage that to be larger
if getting a 2 TB
bumping sys drive to 50 GB is good idea




I believe WHS automatically sets the system partition to 20GB during its setup and uses the remainder as a 'system' data drive but cannot recall for sure. WHS certainly handles files VERY differently than conventional storage due to flexibility in expanding HDD space. I do not want parts of my data on a system drive partition that may complicate any recovery through the "reinstall" that is necessary for a new HDD. I would rather add 'data' drives if this is the case.

Are you speaking specifically to WHS - or offering general advice?


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noxchoIT Product Manager
Top Expert 2009

I would go with 2TB drive as you could need to use more and more drives to extend your storage when the current one exceeds the size later. Yes, disk management in WHS allows extending the current configuration to use more space but it is better to set and forget.


Although I am not familiary with WHS 2008, could you 'clone' your failing drive to the new drive to avoid a rebuild?



Top Expert 2016

since we are dealing with WHS2008 the size of the system drive is not an issue.. having lots of storage drives/space is more important.
My current configuration is adequate and I do not need to add storage but I do already know how. The issue here is how WHS supposedly handles management of the data in relation to the system drive when others are present. The system drive is not used unless you run out of space on your 'other' drives. This is all handled transparently by WHS.

Thanks. Imaging a WHS System drive is apparently bad news. Essentially, it does its own job of managing files in a virtual manner and 'knows' the drives that are connected (or disconnected). Even though the image would be accurate, WHS would reject the drive, knowing it has been changed and your files will get messed up. There is info out there to "make it work" via registry edits etc but it's work work (and risk) than it's worth.

Thanks for your input. The way WHS works is that it uses additional storage before it resorts to using the system disk. This is good as there seems to be less risk of data loss when you do not have data on the system drive. This was the reason for my original post - you can certainly have a large system drive but it seems better to have your 'capacity' as additional drives instead and I was looking for experience/feedback on that.

ALL - Summary/Wrap up
Thanks for all your attempts at helping but, I had to make a decision/purchase to implement - hopefully before it fails.

Due to the apparent manner in which WHS handles files - to me - it does not make sense to use a more expensive 2TB (+?) HDD as the system disk when you have adequate additional storage on other hard drives. As a result, I have purchased a 1TB Seagate Constellation HDD as a replacement system drive due to higher reliability under heavy use and for economics of storage space vs cost. I would have gone with a 500GB (current system disk size) but it was not as cost effective.


As posted above, I had to make a decision.

Hopefully that decision will result in a more reliable solution (Enterprise class HDD) and be the most efficient with storage use/cost.

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