I know that you can only have 4 primary partitions on a hard drive. But if you're using less than 4, is there a benefit/penalty for using logical partitions?
Today, it doesn't really matter if you use primary or extended partitions.
There have been times where /boot had to be a primary partition but this isn't true any more. Also earlier incarnations of MS Windows required that you installed Windows to a primary partition.
When I set up a new disk, I make the first partition primary and put /boot there and put the rest as logical partitions into one big extended but this is just a personal preference.
I would say that there is indeed some penalty if you use logical instead of primary partitions:
- Primary Partitions reside on the first sector - that is a well known place - as opposed to an extended partition.
- AFAIK BIOS will still only boot from an active primary partition - so you have the choice to put any bootloader on any of those partitons and make it active.
So if you have up to 3 partitions keep them primary. If you have 4 or more, use the 4th as extended partition and start using logicals.
Anyway, you're best if you can having as few partitions as possible. Multiple partitions actually slow seek and access times. Many OS's utilize large partitions and its free space for the systems needs.