Debian

The single partition (plus swap space) per disk scheme is the most common nowadays, as it is simple to create and manage. Multiple partitions may be used in the special cases mentioned previously, although, in general, the quality and speed of current backup utilities minimizes the need for separate partitions just for backup efficiency. Ifthe system has multiple disks and may require resizing or live migration in the event of hardware changes, then L VM should be considered.

If available, a swap file or partition is used by Linux when memory paging to disk is necessary. With the advent of cheap memory, such paging is often infrequent with one exception: system hibernation. This is where the system is paused and the memory contents are written to disk prior to power off in order to allow the system to resume from the saved state. While this is commonly associated with laptop systems, servers sometimes make use of it as well.

Logical Volume Management, or LVM, is a format pretty much exclusive to Linux. It is an alternative to partitions which makes space management much easier. Logical volumes can be resized at will, and can span multiple disks. They can be migrated to different disks without interrupting services (live migration). There are also striping and mirroring features that are similar to RAID 0 and RAID 1.

LVM is more complex than basic partitioning, and not commonly used except in large storage installations.

Aside from backup, recovery, and damage limitation, there are administrative functions that may differ depending on how a disk is partitioned. In particular, using a single partition for an entire disk relieves an administrator from having to modify partition sizes if one partition fills up and more space is necessary. TIlls is frequently why a single disk partition (plus swap space) is the recommendation for new users who are uncertain how they want to partition their drives.

Some administrators used partitions to limit the space available for certain directories. A good example is a mail spool directory. A massive spam attack can quickly consume large amounts of disk space. Using a separate partition for the spool directories will limit the total space that can be used by spool files, and the errors generated when no space remains alerts the administrator to the condition.

The availability of account quota systems for Linux can handle this situation without using partitions, but some administrators still prefer the hard limit of partitions.

In the past, backups were performed on full partitions. Large partitions could take a long time to back up, and the system could not write to the partition during the process. With the advent of incremental and live backups, this is no longer a primary consideration. Another problem was that when a disk got corrupted, recovery usually was limited to a single partition. There are partition repair utilities now that can fix most problems (though not all), and only those files that can't be fixed need to be recovered.

The next decision to be made is how to partition the available storage space. There are the following three main considerations when deciding how to partition storage for a Debian system:

• Efficient backup and recovery
• limiting space
• Disk management

Generally, the default ext4 format is the best choice. In specific cases, IFS or XFS may provide some advantages, and if the ability to resize dynamically is more important than performance or scalability, and you don't want to use logical volumes, ReiserFS (especially version 4) might be appropriate. Btrfs should not be used for critical data yet, but at some point soon it will become the preferred format. Non-Linux formats should not be used for the basic system.

Many other formats are available, such as seQ's Unix BFS, QNX, and BSD's UFS. Although Unix-related, they are not considered appropriate for Linux root installations due to slight differences in attribute handling. They may work fine, but the Linux-specific fannats generally have better perfonnance and features.

The Linux kernel supports many additional formats, such as Microsoft's NTFS, the various FAT formats, the old OS/2 HPFS, and Apple's HFS. These formats do not support the attributes required by a Linux system, and are thus not appropriate for a root filesystem. They could be used for other data should it be necessary. Note that these formats lack the basic Linux security attributes, although there is some provision for translating the attributes that do exist into their approximate Linux equivalents.