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All you want to know about Hard Drive Partitions

Disk Partitions

Disk partitioning is the act of dividing a hard disk drive into multiple logical storage units referred to as partitions, to treat one physical disk drive as if it were multiple disks. Partitions are also termed "slices" for operating systems based on BSD, Solaris or GNU Hurd. A partition editor software program can be used to create, resize, delete, and manipulate these partitions on the hard disk.

Nowadays, when the hard drive sizes are increasing unbelievably, every user needs to partition the Hard Disk Drive(HDD) into some partitions according to their needs. All those, who don't know about disk partitioning or the particular disk partitioning method, here is a step-by-step guide divided in several parts to make your mind clear about pros and cons about disk partitioning, for what purposes disk partitioning should be implemented, Disk partition strategies and partitioning the drives with and without third party softwares and much more....

What is Disk Partitioning?
Disk partitioning is a method used to divide the external or internal Hard Disk Drives (HDDs), to use a single hard drive as multiple drives. As they are shown as a independent drive on the File explorer of your Operating System, after partitioning. All the leading Operating Systems has the native functionality to partition a hard drive. Partitions can also be created and manipulated easily by Third-party partition manager softwares.

In which cases I need to partition my Hard Drive?
This is a very common question in a computer user that "Do I really need to partition my Hard Drive?". The answer is "Ask yourself that what you gonna do with this Hard Drive or how you gonna use it."

If you are a computer enthusiast and want to have more than one Operating System (OS) on a single computer, in short, if you want to setup a multi-boot system, then you got to partition your hard drive. Though there exist some other ways like Virtual Hard Drive (VHD), Using Virtual Box, etc. But the simplest and the safest as well as the classical way to setup a multi-boot system is to partition a hard drive into several partitions according to your need of storage and number of partitions you want to setup on a system.

In which cases I need not to partition my hard drive?
If you are not a power user or you just don't want to tweaking your system and if you are happy with the single OS setup, then there is no need to partitioning your hard drive. Even if you have purchased the external hard drive mainly for the backup purposes, then don't bother about partitioning it. Just do what you want, as a single partition will be more efficient and convenient for your needs. 

Benefits of Multiple Partitions
Creating more than one partition has the following advantages:

  • Separation of the operating system (OS) and program files from user files. This allows image backups (or clones) to be made of only the operating system and installed software.
  • Having a separate area for operating system virtual memory swapping/paging.
  • Keeping frequently used programs and data near each other.
  • Having cache and log files separate from other files. These can change size dynamically and rapidly, potentially making a file system full.
  • Use of multi-boot setups, which allow users to have more than one operating system on a single computer. For example, one could install Linux, BSD, Mac OS X, Microsoft Windows or other operating systems on different partitions of the same hard disk and have a choice of booting into any compatible operating system at power-up.
  • Protecting or isolating files, to make it easier to recover a corrupted file system or operating system installation. If one partition is corrupted, other file systems may not be affected.
  • 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 largesequentially accessed Master File Table (MFT) and it generally takes more time to read this MFT than the smaller MFTs of smaller partitions.
  • "Short Stroking", which aims to minimize performance-eating head repositioning delays by reducing the number of tracks used per hard drive. The basic idea is that you make one partition approx. 20-25% of the total size of the drive. This partition is expected to: occupy the outer tracks of the hard drive, and offer more than double the throughput — less than half the access time. If you limit capacity with short stroking, the minimum throughput stays much closer to the maximum. This technique, however, is not related to creating multiple partitions, but generally just creating a partition lesser size than available on the disk.
  • For example a 1 TB disk might have an access time of 12 ms at 200 IOPS (at a limited queue depth) with an average throughput of 100 MB/s. When it is partitioned to 100 GB (and the rest left unallocated) you might end up with an access time of 6 ms at 300 IOPS (with a bigger queue depth) with an average throughput of 200 MB/s.

Disadvantages of multiple partitions
Creating more than one partition has the following disadvantages, as compared to having a single partition spanning the same disk area:
  • Reduces the total space available for user storage on the disk, as it forces the operating system to duplicate certain file system administration areas on the disk for each partition.
  • Reduces overall disk performance on systems where data is accessed regularly and in parallel on multiple partitions, because it forces the disk's read/write head to move back and forth on the disk to access data on each partition and to maintain and update file system administration areas on each partition. It also prevents disk optimizers from moving all frequently accessed files closer to each other on the disk, which could reduce the number and distance of required head movements. Files can still be moved closer to each other on each partition, but those areas themselves will still be far apart on the disk. (See "short stroking" considerations above.) This issue does not apply to SSD drives as access times on those isn't affected by and dependant on relative sector positions.
  • Increases disk fragmentation because it lowers the average size of continuous free blocks on each partition - as compared to a single partition of the same overall size - after the same amount of data has been written to them.
  • May prevent using the whole disk capacity, because it may break free capacities apart. For example, if you have a disk with two partitions, each with 3 GBs free (hence 6GBs in total), you can't copy a 4GB DVD image file on that disk, because none of the partitions will actually provide enough space for that - even though you have more than enough free capacity in total on the disk. If the same files on those two partitions would have been stored on a single partition spanning the whole disk, then the 4GB file could be easily stored in the 6GB of free space.
  • Slows down moving data between different parts of the same physical disk. When moving data from one partition to other, the operating system actually has to copy the contents of the data file, even though it still remains on the same device in a single copy/instance. When using a single partition, moving data between directories will only require altering the file system administration areas, and the actual contents of the file will not be copied or moved inside the disk/device, thus resulting in an indefinitely faster completion of the operation.
  • Hurts portability and might impose constraints on how entities might be linked together inside the file system. For ex. the NTFS file system allows hard links to be created only as long as both the link and the referenced file reside inside the same volume/partition. Also under Windows if you're referencing a file on another partition, you can do that only by specifying the partition's assigned drive letter - which, however, might change with time and depending on the drives installed. This renders references invalid and dependent on actual drive letter assignment, which is not an issue if you have to reference files/directories only on the same partition, as in this case you can use directory-relative or root-relative references, without including the drive/partition letter.

After reading this article, if you have decided to partition your hard drive, then you may need some assistance on how to partition a hard drive and what are the sizes of the partitions you should keep to match all of your needs (Multi-needs, I should say!). Don't worry, here is the help you may need.

Rajat Patel

Rajat Patel

Founder at TheNextGeek.com. Software Engineer & Business Analyst by profession. Avid open source evangelist. Mostly writes about Technology that interests him, and some neat tricks to make your day-to-day tech life a breeze.

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