This question from Jim Bergmann came in for ExtremeTech editor, Loyd Case:
Following the advice of my first computer guru many years ago, I have partitioned my hard drives: C:\Operating System; D:\Data; E:\Programs; F:\Free Space for Future allocation.
The rationale: When the operating system goes crazy, just reformat C:\ and reinstall. Data remains in place and programs are all lined up in E:\ for reinstalling. And why should I want my "bits" floating around 250GB of hard drive space when I'm using less than 50GB?
Now my young neighbor (who lives and breathes computers) advises, "Enter the twenty-first century. Partitioning is unnecessary and counterproductive. It fragments the virtual memory and slows your computer." What say you? To partition or not to partition: That is the question.
See Loyd's reply after the jump.
Loyd's reply:
I get this question a lot, particularly from PC users who remember the era when a gigabyte hard drive might cost you nearly a dollar a megabyte.
Your neighbor is exaggerating the downside of partitioning somewhat. Even today, most Linux distros will partition the drive in ways similar to what you describe. But current versions of Windows, starting with Windows XP, perform better on an unpartitioned drive. Windows likes to optimize the location of frequently used applications and the swap file, and that tends to work more effectively if the drive is one large partition.
Of course, then you run into all the downsides--particularly, potential data loss if you keep your data on the same drive as the OS. On the other hand, if the drive itself fails, then you lose everything anyway. Partitioning is no substitute for backup.
One simple solution in the era of cheap storage is to have two physical drives. Keep the OS on one drive and everything else on a different drive. This spreads the risk somewhat. If you're running Windows Vista, you can put the Windows common file locations, such as Documents and Pictures on the second drive simply by right-clicking on the folder, selecting the Location tab and changing the location. Vista will even ask you if you want to move the existing files to the new location. XP users can right-click on My Documents (which contains, by default, My Music, My Pictures, and My Videos), select Properties, then use the Target tab to change the location of the folder.
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June 24, 2008 9:41 AM
Computing is a large field, so "living and breathing computers" in one specialty doesn't imply knowledge of another. The neighbor is making an appeal to authority (or one is being made on his behalf), so I'll make mine: I've been working on storage and virtual-memory systems for about two decades, and the neighbor is clearly making claims well beyond his specialty. In general, the virtual-memory system *does not care* whether it's fetching data from a partition or a raw disk, and paging space (one contiguous file either way if you set up your system properly) will not become more fragmented one way than the other.
That said, Windows does try to colocate frequently-used files (which in its case includes the page file), and there are a couple of similar projects in Linux. In all cases, the object is to reduce thrashing of the disk heads between one part of the disk and another, and the OS is a bit freer to do this if all of the frequently-used files are on one partition. The effect should not be overstated, however. There are cases where the OS can optimize layouts better, and there are cases where it does a singularly poor job so you're better off using partitions to make sure that files accessed together are located together. The only easily-described case in which I'd recommend against partitions would be an application that does lots of file I/O and also uses lots of virtual memory. In that case having the paging space and the data files on separate partitions would *certainly* induce head thrashing and be bad for performance.
In any case, these concerns must be weighed against the data-management issues of using multiple partitions. If you run multiple OSes, if you want to move or resize, if it simplifies your backup strategy, or for a dozen other reasons, finer-grain partitioning might be beneficial. If these concerns point toward having many partitions but you also want higher performance, get a caching RAID controller. You'll notice far more of a difference than you would by using a tweaking partition layouts, without having to give up any benefits of partitioning.
BTW, you should tell the neighbor that the twenty-first century is all about virtualizing everything, and partitioning is a primitive form of virtualization. If enterprise and HPC users aren't slicing and dicing their storage via partitioning, it's only because they already do that at the disk-array level or with a dedicated storage-virtualization appliance. "Everything in one big bucket" is sooo last century. ;)
June 26, 2008 5:58 PM
The neighbor is wrong. The page file only gets fragmented if you have little free space, it has nothing to do with partitions. The other thing is that the page file is dynamic by default, meaning that it will shrink or expand, depending on the needs. This can be avoided by creating a static page file roughly 1.5 times the size of memory.
It's always better to separate data from the system, not only does it make it easier to backup the system (you only need to make an image of the partition which with 100% certainty will contain ALL system files), it also makes it easier to backup your data. It's also more transparent to other users, all you have tell them is to backup everything on D: and they'll be fine, taken in account that a scheduled backup runs at al time to backup D: of course.
June 27, 2008 12:53 PM
I think you are forgetting that the read / write speed varies across a disk.
Reading or writing is faster on outer tracks than inner tracks. The difference can be as much as 200%. Therefore, if you use multiple partitions, the partitions that are closer to the center of the disk are going to be the slowest partitions. In your example, that is where the programs are (drive E:).
I think file placement on the disk is more important than file separation. There is software out there to put "high-performance" files on the faster outer tracks and non-important or archival files on the slower inner tracks out of the way.
If file separation is important to you, then do it across multiple drives not within a drive. It is better to have multiple drives (with "high-performance" files stored on outer tracks) for the fastest speeds than multiple partitions on the same drive.