Editing File system (section)

===Converting the type of a file system===
It may be advantageous or necessary to have files in a different file system than they currently exist. Reasons include the need for an increase in the space requirements beyond the limits of the current file system. The depth of path may need to be increased beyond the restrictions of the file system. There may be performance or reliability considerations. Providing access to another operating system which does not support the existing file system is another reason.

====In-place conversion====
In some cases conversion can be done in-place, although migrating the file system is more conservative, as it involves a creating a copy of the data and is recommended.<ref name="ms">{{cite web|url=https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-xp/bb456984(v=technet.10)|title=How to Convert FAT Disks to NTFS|website=[[Microsoft Docs]]}}</ref> On Windows, FAT and FAT32 file systems can be converted to NTFS via the convert.exe utility, but not the reverse.<ref name="ms" /> On Linux, ext2 can be converted to ext3 (and converted back), and ext3 can be converted to ext4 (but not back),<ref>{{cite web|url=https://ext4.wiki.kernel.org/index.php/Ext4_Howto#Converting_an_ext3_filesystem_to_ext4|title=Ext4 Howto|work=kernel.org|access-date=29 April 2016}}</ref> and both ext3 and ext4 can be converted to [[btrfs]], and converted back until the undo information is deleted.<ref name="btrfs">{{cite web|url=https://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3|title=Conversion from Ext3|website=Btrfs wiki}}</ref> These conversions are possible due to using the same format for the file data itself, and relocating the metadata into empty space, in some cases using [[sparse file]] support.<ref name="btrfs" />

====Migrating to a different file system====
Migration has the disadvantage of requiring additional space although it may be faster. The best case is if there is unused space on media which will contain the final file system.

For example, to migrate a FAT32 file system to an ext2 file system, a new ext2 file system is created. Then the data from the FAT32 file system is copied to the ext2 one, and the old file system is deleted.

An alternative, when there is not sufficient space to retain the original file system until the new one is created, is to use a work area (such as a removable media). This takes longer but has the benefit of producing a backup.