How do I partition a portable drive?

What is Disk Partitioning?

Disk partitioning is the act of dividing a hard disk drive into multiple logical storage units called partitions. Partitions behave like separate physical drives, allowing you to have different file systems or operating systems on the same disk.

There are several reasons why you may want to partition a disk:

  • Organize data – You can separate different types of files like documents, photos, videos onto their own partitions.
  • Run multiple operating systems – Partitioning lets you install different OSes like Windows, Linux, macOS on the same drive.
  • Enhance performance – Important system files can be put on faster partitions for quicker boot times.
  • Separate data – Keeping personal data in a different partition can prevent corruption.
  • Increase available space – Partition sizes can be changed to make more room if needed.

Partitioning allows better organization and flexibility in how the storage space on a drive is utilized. The partitions appear as distinct drives, helping to logically separate data and programs.

When to Partition a Portable Drive

There are a few key reasons you may want to partition a portable drive:

When you want to use the same drive for multiple operating systems – Partitioning allows you to install different operating systems on separate partitions of the same drive. This lets you boot into different OS without having to swap out drives. For example, you could have a Windows partition and a Linux partition on the same external drive for use between different computers (source).

When you want to separate data types – Creating separate partitions for documents, photos, videos, music etc. can help keep your data organized and easy to find. Different types of data may also benefit from different file systems. For example, you may want a FAT32 partition for general files and an NTFS partition for larger media files.

Partitioning Tools

There are several partitioning tools available to help partition a portable drive in Windows and Mac OS. The main options are:

  • Built-in disk management utilities like Diskpart on Windows and Disk Utility on Mac provide basic partitioning capabilities.
  • Third party partitioning tools offer more advanced features and flexibility:

Third party tools allow more control over partition alignment, copying, resizing, merging and splitting. They include features like SSD optimization, recovery tools, and bootable media creation.

Partition Schemes

The two main partition schemes for hard drives are Master Boot Record (MBR) and GUID Partition Table (GPT). They have some key differences:

MBR is the older legacy partitioning scheme that has a limit of 4 primary partitions per disk. To get around this, you can create extended partitions that contain logical drives. MBR partition tables are limited to 2 TB partition sizes. MBR uses 32 bit logical block addresses. The main advantage of MBR is compatibility with older operating systems and bootloaders that do not support GPT.

GPT is a newer standard that lifts many of MBR’s limitations. GPT supports up to 128 primary partitions per disk with no need for extended/logical partitions. GPT also supports much larger partition sizes up to 9.4 ZB. GPT uses 64 bit logical block addressing for larger disk and partition sizes. GPT includes cyclic redundancy check values for better data integrity. The main advantages of GPT are increased flexibility, capacity, and reliability. (Source)

For boot drives, Windows 7 and earlier require MBR partitioning while Windows 8 and later support both MBR and GPT. For data drives, both MBR and GPT will work on modern Windows versions.

Creating Partitions

There are three main types of disk partitions to be aware of when partitioning a drive in Windows:

  • Primary Partition: Primary partitions contain the operating system and can be booted from. Up to 4 primary partitions can be created on a hard drive.

  • Extended Partition: An extended partition is a container that allows you to create multiple logical drives within it. There can be only one extended partition on a disk.

  • Logical Drive: A logical drive/partition resides inside an extended partition. There is no limit on the number of logical drives you can create.

When determining partition size, consider the type and amount of data to be stored, leaving room for growth. As a rule of thumb:

  • OS partitions: 50-100GB for Windows and Linux installs.

  • Data partitions: Depends on storage needs. Make partitions only as large as required.

  • Leave 10-20% of drive space unallocated for future flexibility.

The Windows Disk Management utility makes it easy to create, delete and resize partitions. Be aware that creating or deleting partitions will erase existing data.

Formatting Partitions

Once you have created partitions on your portable drive, the next step is to format them with a file system. The file system defines how data is stored and retrieved from a partition. The main options for file systems on Windows are NTFS, exFAT, and FAT32.

NTFS is the most modern file system from Microsoft. It supports large partition sizes up to 256 TB and large individual file sizes up to 16 TB. NTFS has advanced features like file compression, encryption, permissions, and disk quotas. However, NTFS is proprietary to Windows and read-only on macOS by default.[1]

exFAT is optimized for flash drives and external hard drives. It works across both Windows and macOS with read/write support on both platforms. exFAT supports large partition sizes up to 128 PB and large file sizes up to 16 EB. However, exFAT does not have as many advanced features as NTFS.[2]

FAT32 is an older file system that has maximum partition and file sizes of 32 GB and 4 GB respectively. It has limited features but wide compatibility with all operating systems. FAT32 works well for small USB flash drives.

For portable drives that will be used across both Windows and macOS, exFAT is generally the best option. It has broad compatibility while still supporting large drives up to 128 PB. NTFS can be used for drives that will be exclusively or primarily used on Windows. FAT32 is best for small flash drives under 32 GB in size.

Moving Data Between Partitions

There are a couple ways to move data between partitions on a portable drive:

Using copy/paste or drag and drop – Once you have both partitions mounted, you can simply copy/paste or drag and drop files between them as you would between any folders. This is the simplest method for moving a few files.

Third party migration tools – For moving many files or entire folders, a third party migration tool like Syncthing can automate the process. These tools allow you to set up one-way or two-way syncing between source and destination folders on different partitions.

Migration tools are especially useful for ongoing syncing after the initial move. They can watch for changed files and continually sync partitions in the background.

Partition Alignment

Partition alignment refers to how partitions of a hard drive are mapped to the physical sectors of the drive’s disk platters. Due to advancements in hard drive technology, such as 4K sector sizes, misaligned partitions can cause a number of performance issues.

Misaligned partitions happen when the logical sectors used by the operating system do not line up with the physical sectors on the disk. This can cause excessive read-write head seek times as the head moves back and forth between mismatched logical and physical sectors. It can also introduce added latency as the drive firmware has to do extra work to translate between misaligned logical and physical addresses.

To check for partition alignment issues, you can use tools like GParted or third-party partition alignment software. These will analyze your partition layout and alert you to any potential misalignments. They may also provide options to automatically align your partitions properly.

Fixing alignment issues is as simple as deleting misaligned partitions and recreating them with alignment enabled. This realigns the partitions to match up cleanly with the physical sectors. Just be sure to backup any data first before deleting partitions.

Potential Issues

There are some common partitioning errors that can occur when partitioning a portable drive:

Not enough free space – This error occurs when you try to create a new partition but don’t have enough unallocated space on the disk. To fix this, you may need to delete or shrink an existing partition first to free up space.

Invalid partition size – Some partition managers may reject the size you specify for a new partition. Make sure the size is within the minimum and maximum allowable sizes.

Incorrect partition alignment – Partitions should be aligned to optimize performance. Misaligned partitions can cause performance issues. Use partitioning tools that align partitions automatically.

“Disk read error” – This usually means there is a hardware problem with the disk itself. Try the disk in another system to confirm. The disk may need to be replaced if it’s faulty.

“Partition overlaps existing partitions” – This error occurs when trying to create a new partition in disk space already occupied by another partition. Delete or shrink the overlapping partition first.

Accidental partition deletion – This is easy to do by mistake. Try restore tools to recover the partition, and be careful when managing partitions.

Corrupted boot sector – Sometimes the boot sector can become corrupted, making partitions inaccessible. Try using boot repair tools like the Windows installation media.

Unassigned partition space – This “unallocated” space is common after deleting partitions. It can be assigned to a new partition.

Problems during format – The format process can sometimes fail. Try formatting again or check for file system errors.

Partitioning Tips

When partitioning a portable drive, it’s important to follow best practices to avoid potential issues. Here are some dos and don’ts to keep in mind:

  • Do back up your data before partitioning. This allows you to restore your data if anything goes wrong during the partitioning process. (Source)
  • Don’t partition the drive while it has data on it. Deleting or overwriting data during partitioning can lead to permanent data loss. (Source)
  • Do choose an appropriate partition scheme based on your needs, such as MBR or GPT. The partition scheme can’t be easily changed later. (Source)
  • Don’t create too many partitions, as this can negatively impact performance. Stick to 2-3 partitions maximum. (Source)

Following best practices like backing up your data and choosing the right partition scheme will help ensure a smooth partitioning process without lost data.