New Hard Drive

[gbalonek]

I am going to be installing a new 500GB Hard Drive when Windows 7 comes out. I will have a second 400GB Hard Drive (existing) for storage of files, etc.

For the new Hard Drive, what are the pros and cons to setting up two partitions (C: & D? In the past, my C: Drive was the O/S and other programs. D: was used for storage, but I will be using the 400GB for that.

 

[sminlal]

I am of the opinion that splitting a drive into multiple partitions is a bad thing. There are two reasons for this:

a) You can run out of room in one partition while space is available in the other.

b) Partitions force the disk access arm to move farther, hurting performance.

I occasionally create multiple partitions when I'm trying to characterize the I/O load of a system and I only have one drive available - the performance monitoring tools can show I/O per logical drive letter and this helps to determine which files or folders are getting hit the most. But for real use I stick to one partition per disk.

There is, however, a reason why you might want to partition a large drive down to a smaller one. If you need, say, a 100GB drive to hold the OS, then buying a much larger drive and partitioning it down to 100GB (and leaving the rest unused) could give you slightly better performance. This is because the heads won't have to move as far to access data anywhere in the smaller partition. Mind you, a good disk defragmenter which moves all the files to the smallest LBN numbers will effectively do the same thing.

 

[aford10]

The amount of room on a partition can be altered w/ partition magic.

The smaller partitions will speed up access times, as there isn't as much storage space to scan.

 

[sminlal]

The smaller partitions will speed up access times, as there isn't as much storage space to scan.

That's not true, at least not if there's any free space in the partitions.

For example, if you split a 500GB into two 250GB partitions, C: and D:, then the disk is going to have to move the heads across nearly half of the disk every time it alternates between reading something from C: vs. reading something from D:

The best thing to do from a performance perspective is to have one partition and defrag the drive so that all the files are at the lowest possible LBNs. That will minimize head movement and therefore maximize performance.

 

[aford10]

http://en.wikipedia.org/wiki/Disk_partitioning

- Raising overall computer performance on systems where smaller file systems are more efficient. For instance, large hard drives with only one NTFS file system typically have a very large sequentially-accessed Master File Table (MFT) and it generally takes more time to read this MFT than the smaller MFTs of smaller partitions.

- "Short Stroking" aims to minimize performance-eating head repositioning delays by reducing the number of tracks used per hard drive.[1] The basic idea is that you make one partition approx. 20-5% of the total size of the drive. This partition is expected to: occupy the outer tracks of the hard drive, more than double the throughput, more than half the access time. If you limit capacity with short stroking, the minimum throughput stays much closer to the maximum.