MBR vs. GPT

If you want to integrate a new hard drive into an existing system, or reinstall your operating system, the first step is to format the hard drive. This allows the storage medium to acquire, store and process data as required – among other things thanks to com­pat­ible file systems such as NTFS or FAT. A basic part of the format­ting process is par­ti­tion­ing, i.e. dividing the available memory into several in­de­pend­ent areas – the par­ti­tions (or “drives”).

To split up a disk into multiple par­ti­tions, you have to use a special table known as a partition table. Choosing a suitable table basically comes down to one question: MBR or GPT? It doesn’t matter whether you’re using Linux, Windows or Mac. For all operating systems, these two tables are the only two solutions for par­ti­tion­ing. But what’s the dif­fer­ence between them? And which one is best – MBR or GPT?

Splitting up hard drive space on well-known operating systems like Windows is something of a tradition, but it is not actually necessary. Any storage medium can be used without dividing up the memory, providing that it has been formatted with a file system that is supported by the operating system in question. So why is par­ti­tion­ing so popular when it comes to hard drive man­age­ment? The answer lies primarily in its ad­vant­ages, which can be sum­mar­ised as follows:

• The operating system and system-related services such as a boot loader can be stored in the fastest part of a hard drive (usually the outside of the disk), in order to ensure maximum read and write speeds.
• Data that is not modified very often can be put in a separate partition as an easy way of excluding it from regular de­frag­ment­a­tion.
• In general, system and ap­plic­a­tion programs can be easily separated using par­ti­tions, which makes it much easier to do system backups or in­di­vidu­al data backups.

Along with the IBM Personal Computer XT and PC DOS 2.0, 1983 saw the in­tro­duc­tion of the Master Boot Record (MBR). Since then, the system component has been used on the one hand as a boot manager to boot (and install) BIOS-based computer systems, and on the other hand as a partition table to ef­fi­ciently split up the available memory. This second function is what helped MBR quickly become the standard for all kinds of storage devices, for example hard drives, USB sticks and memory cards. More recent systems now in­creas­ingly use MBR’s official successor, the GUID Partition Table (GPT). This new partition table standard is a component of the UEFI spe­cific­a­tion which was in­tro­duced in 2000 and has steadily been gaining pop­ular­ity as an al­tern­at­ive to BIOS.

The MBR partition style shaped computer tech­no­logy for many years, but it non­ethe­less has some sig­ni­fic­ant lim­it­a­tions which meant it was only a matter of time before a successor came along.

For example, right from the beginning, one of the key weak­nesses of the Master Boot Record was that the tech­no­logy only supports four primary par­ti­tions. Anyone wanting to set up more than four areas has to use “extended par­ti­tions”, and although these can be split up into as many “logical par­ti­tions” as desired, the resulting memory structure is complex, and hardware faults can quickly lead to data loss.

Another even more obvious problem with the tra­di­tion­al par­ti­tion­ing concept is that MBR par­ti­tions can only be used on hard drives or storage devices up to 2 terabytes (2,000 gigabytes). It’s true that for many decades that was more than enough, but nowadays it is too small even for standard drives used by private users. Alongside the increased security, the greater storage capacity has also been a key factor in the de­vel­op­ment of GPT as a successor for MBR.

When de­vel­op­ing the GUID partition table, one of the aims was to address the above­men­tioned weak­nesses of the Master Boot Record. The result was a partition standard that has clear ad­vant­ages in terms of security and per­form­ance. The following table sum­mar­ises the key dif­fer­ences between MBR and GPT:

If you want to set up par­ti­tions on a storage device, both MBR and GPT will usually still be offered as options. However, in principle GUID partition tables have become the standard solution for modern hardware because they support an unlimited number of par­ti­tions and have no re­stric­tions as regards the size of the storage device or the par­ti­tions (or at least none that will become relevant in the near future). Moreover, for disks with more than 2 terabytes of memory, GPT is the only solution. The use of the old MBR partition style is therefore now only re­com­men­ded for older hardware and older versions of Windows and other older (or newer) 32-bit operating systems.

If you are using disks par­ti­tioned using the Master Boot Record this isn’t a problem, but it is worth re­mem­ber­ing that there is a higher risk of data loss in the event of a hardware fault. Con­sid­er­ing this, providing your system offers the necessary support for GUID partition tables (i.e. a modern 64-bit system; for Microsoft this means Windows 7 or higher), we recommend that you convert your existing MBR par­ti­tions to GPT par­ti­tions. There are special tools for doing this, although many systems have a built-in con­ver­sion solution.

In Windows for example, you can convert par­ti­tions using the “Disk Man­age­ment” tool. The steps are as follows:

1. Open the control panel and click on “Ad­min­is­trat­ive Tools”.
2. Find the icon for the “Computer Man­age­ment” service and double-click on it.
3. In the menu pane on the left, select “Disk Man­age­ment” (listed in the “Storage” section).
4. Windows will now show you a list of the disks set up on your device, including any par­ti­tions that have been con­figured. Right-click on the relevant storage device and select “Convert to GPT disk”.

Users of Linux operating systems such as Ubuntu can convert par­ti­tions via the terminal, using the gdisk program.