What is the maximum number of partitions that can be made on a hard drive?

Question

What is the maximum number of partitions we can make on hard disk in windows?

If it is limited to some particular number why they have they provided until letter Z to assign? If it is a special case, whats that?

Answer 1

You can have 4 primary partitions, or 3 primary partitions and one extended partition containing any number of logical partitions. While you can assign a drive letter to a partition, you can also map it as a folder in modern versions of windows, allowing more partitions, or use subst to mount it to a number.

In linux since everything is on mountpoints, partitions are a non issue - you just need to make sure you have enough device letters (sda-sdz) and any arbitrary number of partitions on it.

The EFI specification mandates that a GUID Partition Table (GPT), which all modern operating systems support, be capable of containing a minimum of 128 partitions of any size. This partitioning scheme is starting to get widespread adoption with UEFI being natively supported by modern computers and the need to boot from HDDs larger than 2TB.

Answer 2

On a disk using the traditional MBR format, the partition table has four slots. Each can hold a "primary" partition, or one can be used to create an "extended" partition which can contain any number of sub-partitions (often called "logical drives"). Extended partitions are basically a workaround for the small size of the MBR partition table, and there are limitations on what they can be used for. (For example, the Windows bootloader must be on a primary partition.)

The newer GPT disk format supports many more partitions — technically unlimited, I think, but operating systems impose a limit of 128. These are all "primary" partitions (to use the MBR terminology).

Answer 3

From Technet: Reviewing Storage Limits: Local File Systems:

The number of disk drives you can use for each server is limited only by the available memory for FAT16, FAT32, NTFS, and UDF files systems.

So no there is no hard limit on Windows on the number of drivers. Drive letter are of course limited, since they stop at Z. But drives don't have to be given a drive letter - they can be mapped to a folder on another drive. From the same Technet article:

Mounted drives are useful when you want to add more storage to an existing volume without having to extend the volume. A mounted drive is a local volume attached to an empty folder on an NTFS volume. Mounted drives are not subject to the 26-drive limit imposed by drive letters, so you can use mounted drives to access more than 26 drives on your computer. For more information about mounted drives, including information about creating mounted drives on server clusters, see "Using NTFS mounted drives" in Help and Support Center for Windows Server 2003.

Answer 4

Hard disks can be split into four primary partitions, or one of these can be configured as an extended partition.

An extended partition can theoretically contain an infinite number of logical partitions, and so while Windows only has drive letters up to z: (plus some other characters) this is not a limit on the number of partitions you can create, even if you can't assign a drive letter to them.

Answer 5

Theoretically, an unlimited number of partitions can be created in a drive. The total number of partitions is limited by the amount of space that is reserved for making partition entries.