Does having more that one partition on a hard drive affect performance?

Question

Possible Duplicate:
Why use multiple partitions on Linux installations?

I'm building a new computer and want to maximize the performance of each component.

In the past, I've generally partitioned my hard drives into multiple primary and extended logical volumes. I do this to accommodate several operating systems.

Now, the question I'd like to ask is will having multiple volumes in the manner described negatively impact overall performance of the drive?

The drive in question is a WD Caviar Black 7200 RPM 1TB drive connecting to a SATA III 6Gb/S controller.

My partitioning scheme as currently planned:

/dev/sda
    /sda1  (Windows XP, NTFS, 25GB)
    /sda2  (Windows 7, NTFS, 50GB)
    /sda3  (Linux root, EXT4, 25GB)
    /sda4  (extended)
           /sda4(1) (Linux /home, ETX4, 400GB)  
           /sda4(2) (Generic storage, NTFS, 525GB)

Answer 1

In practice, NO.

Theoretically, under some circumstances YES. Based on the speed of the disk platter passing beneath the read/write heads and the distance they must travel.

One thing is because you've decreased the size of the disk partition available to the OS, it has less distance to travel. So seeks should be faster than if the whole 1TB was available to any one OS.

In terms of day to day running you won't be able to tell any difference unless you did some before & after testing using disk performance testing software.

But, there are so many different factors involved that determine performance including the type of file system, sector size, size of files being read, fragmentation level (and the list goes on) that you couldn't generalize it.

I would say, don't worry about it. Do what you plan and it'll be fine.

Answer 2

No. It just affects how much the operating system has to add to get to the correct LBA. Which it is always doing even if it needs to support a single partition.

You might get a very, very marginal and imperceptible increase in performance if you use a kernel with partitioning disabled (you'd just install things on /dev/sda directly), but I don't know if that's possible, and you couldn't use the 99.99% of disks with a partition table on it properly.

Answer 3

In a word: Yes.

Think of it this way: Every time your system needs to load a program and data, it has to seek to the partition with the code, then move the heads all the way to your data partition at the other end of the disk. You've guaranteed that any seeks are found to be 3/4 stroke, I'd not full stroke seeks.

Now, the differences might not be too terrible in practice, and lots of other variables come into play with a loaded and running modern OS.

The same principle is applied, in reverse, when short stroking a larger drive. Capacity is traded off for a reverse in seek times and an increase in performance.