The 'C' Drive. How large should it Be ?

Hi.   The is a subjecct I have often wondered about, ands have come to my own conclusion.

But would be interested in any views on the matter.

I have long felt that the 'C' drive should contain the Operating System, and the Program Files with Essential Data that needs to be installed on, and sufficient free space  so that lack of 'Paging' space doesn't slow things down.    

But very little else.  All Data files should be on 'Other' drives, and backed up accordingly, and they are probably of the most importance.  

So what would be the ideal size to use as a 'C' drive ?    110 ?  250?   1TB [ Surely too much!]

And are there any reasons against using a smaller drive for the 'C' ?

Look forward to comments.
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Gary CaseConnect With a Mentor RetiredCommented:
If your desktop has an available PCIe slot (it most likely does, as it has 2 x1 slots), this is an excellent USB3 card:

For the laptop, if you want faster access, I'd connect a NAS unit.   Since the laptop has Gb Ethernet, that will be notably faster than USB2.
Depends. Most people are using their 'My documents' folder (which they absolutely should) to save their stuff so it grows. Also applications these days such as Adobe suite only requires 16GB just for installation.

Personally I do at least 80GB or depending on the drive size. My desktop PC has 200GB SSD so that's my C: drive and additional drives plus iSCSIs are additional drives.

The purpose of a C: drive is to have all applications, windows and user files in one place. Nowadays you can just refresh the system (since W8) so you don't need to worry about offloading plus SkyDrive/dropbox keeps everything in sync so to lose something is more of a neglect rather than 'I didn't know' issue as it used to be.

The reasons against smaller drives are only speed (mainly for SSDs) and running out of space. Just on the weekend we ran out of space on our dedicated Exchange server - dedicated C: with 60GB wasn't enough for some reason.

The question is always about the future, space and requirements so there isn't a general rule of thumb.
I am totally with you that the C: drive doesn't need to contain any data at all.

It depends however if you are talking about a desktop OS, or a server one. For a Desktop OS I would use 80GB as a minimum. For a server however I only use 65 / 70 GB.

I just use the C: drive for the OS. Further I would use a second drive (or partition) for data and installed applications.
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I vote 500GB. Use a 500GB 10,000RPM drive, create a single partition.

If you go any smaller than that, use an SSD drive... 240-256GB SSD drives are reasonable now... $120 to $150.

Still, I wouldn't bother splitting up larger drives... no sense segregating them. When C: dies it's most-likely going to take the other partitions on the drive with it.
I'd go 100mb for C:. Store your data on a separate partition. If you need to reinstall the OS all your data will still be intact. You can redirect your "My Documents" to the second partition as well.
it depends on what you want, and in which envoronment, personal, or business.
for simplicity for a single user, best leave everything on 1 drive, 1 partition
if you want data separated - use a second drive.
in this case the max size depends on what you want to install - but i am using an 160 GB SSD for years, and it's about 1/2 full.
so an 80 Gb  drive is a bit small, but 120 GB can do -  for Win 7 - 64 bit
Gary CaseConnect With a Mentor RetiredCommented:
With XP I always found 40-60GB was plenty for the OS and all programs ... and I have a LOT of programs installed.    Vista and '7 need more, so I started making it 100GB, which has been more than adequate for a very-well-loaded '7 system.

I now use 120GB, as all of my systems have SSDs for the OS drive, and that's a convenient size SSD.

As for segregating data from the OS => I definitely agree.    If you store all of your data on a different drive [Note that "drive" can simply be a different partition], then you can IMAGE the OS periodically and if something corrupts the OS (virus, install gone bad, a rogue program, etc.) or the drive fails, all you have to do is restore the OS from the latest image, and all of your data is intact.     The image doesn't need to be done very often -- I do it once/quarter -- since the OS install likely doesn't change much (except for Windows and program updates, which will automatically be done after you restore the image).

Another advantage of segregation is that if you have a multi-boot system, you can "point" all of the OS's to the same data partition, so no matter which OS you boot to, your data is always available.    This used to be much more useful than it is these days, as I now use VM's instead of multiple boot partitions, but I'm sure it's still useful for some.
Pramod UbheCommented:
I would recommend 40GB for 2003 and 60 GB for 2008 however you need to make sure no other data resides on C: drive  e.g. program files can be on diff drive (at least for heavy applications like SQL) and IIS log files (or you can archive them periodically).
If your users don't have a habit to store data on servers, user profiles will not make much diff.

This has been our standard since long and did not faced any disk space crunch if you follow all the rules.
Pramod UbheCommented:
If you need to define your standards, what will reside on C: drive on a generic server or the sever role that has major contribution in the your server count. just calculate everything on one of the servers and decide how far your planning should be - like 3years, 5 years etc. Depending on that you can decide whether to go for 100GB or 200GB or anything else.

Remember that over a period of time WINSXS folder consumes around 20-30 GB space in 2008 and you cannot delete anything in it.
"C" usually hosts program files so I guess it's all up to you,how many programs do you intend to have?  I guess 200 GB is just about right.
The question leaves nearly no room for discussion. Any windows version will need a defined space + pagefile (which depends on your RAM size) + (if needed) hiberfile (again RAM-dependant), the driver are neglectible. So all space going beyond is windows updates and installed programs. So please take win7, install it, and see how much room it needs. Then install SP1, then all updates. You will see it has grown. Then do an update cleanup (a recent update enables win7 to lose some weight by running the system cleanup wizard against updates, too) and look at the numbers again.
Of course this will be nowhere next to 80 GB , even on x64 with hiberfile on (and 16 GB RAM). Let's say OS maybe 30 GB, hiberfile 16, pagefile 16 (24?), altogether maybe 70 GB max.

Nearly all the big stuff people keep on c: is their own work. Large apps, large films/music/photos in their library folders. That is the big X in your equation.

There are apps that use 10 MB, while others use 50 GB (Example? Autodesk inventor 2014). Very, very hard to plan with if you have no clue where the machine is heading.

So if you are sure there won't be much stuff installed, 100 GB will be absolutely fine even in the long run. You could take less, but you never know - think of an OS upgrade... Setup will tell you "at least 20 GB free space is needed for the upgrade process to succeed".
fried-chipsAuthor Commented:
Thanks for all the comments.    It's interesting to me that several of you use SSD drives, which is something I have never got into.   Maybe i should.

My whole approach   has changed over the years, especially with the cost of standard storage, [ SATA Drives etc] falling so low.   The difference in cost between a 120 GB and a 250 Gb is not huge.  So I have been using 250 GB for the 'C' drives, which are purely for OS, Programs, and Updates.    Overkill really.   Could probably use half that.

Everything else , including User Docs, Downloads, Pics, Music, Videos etc are routed through USB to a 1TB drive.
This is backed up nightly to another 1TB, which is also copied to a third 1TB.  

External or Internet type backups are not really possible for me, as I live in the mountains, with no Broadband coverage, so have to use Mobile Data through a Pocket Wi-Fi unit and a Cellfone Sim Card.    Works fine, but I do have to watch the Data usage !!

I also have a copy of a Program called DISK IMAGE, which I run overnight once a month, in case I have to do a complete restore.   I have had to twice now over the last 6 years, and it has proved invaluable !!

Obviously from this method you will deduce that speed is not critical for me, or I wouldn't be able to use the drives through a USB Hub.

But SSD for the 'C' drive sounds interesting.
nobusConnect With a Mentor Commented:
for backups - i suggest that you look for an USB 3.0 card if your PC does not have it
then buy an USB 3.0 external drive for backups -  very FAST
i use the seagate 3 TB drive :
fried-chipsAuthor Commented:
A couple of the WD drives I have are USB3 capable, but as I have them often connected to an older Laptop [Acer Extensa 5220], I'm not sure if there's any way to fit a USB3 output to it.

Probably OK with my INTEL DH55HS M/B  though on the desktop.
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