Editing Backup (section)

===Filesystems===
*Filesystem dump: A copy of the whole filesystem in block-level can be made. This is also known as a "raw partition backup" and is related to [[disk imaging]]. The process usually involves unmounting the filesystem and running a program like [[dd (Unix)]].<ref name="PrestonBackup07">{{cite book |url=https://books.google.com/books?id=6-w4fXbBInoC&pg=PA111 |title=Backup & Recovery: Inexpensive Backup Solutions for Open Systems |author=Preston, W.C. |publisher=O'Reilly Media, Inc |pages=111–114 |year=2007 |isbn=978-0-596-55504-7 |access-date=8 May 2018}}</ref> Because the disk is read sequentially and with large buffers, this type of backup can be faster than reading every file normally, especially when the filesystem contains many small files, is highly fragmented, or is nearly full. But because this method also reads the free disk blocks that contain no useful data, this method can also be slower than conventional reading, especially when the filesystem is nearly empty. Some [[filesystem]]s, such as [[XFS]], provide a "dump" utility that reads the disk sequentially for high performance while skipping unused sections. The corresponding restore utility can selectively restore individual files or the entire volume at the operator's choice.<ref name="PrestonUnix99">{{cite book |url=https://archive.org/details/unixbackuprecove00wcur |url-access=registration |title=Unix Backup & Recovery |author=Preston, W.C. |publisher=O'Reilly Media, Inc |pages=[https://archive.org/details/unixbackuprecove00wcur/page/73 73]–91 |year=1999 |isbn=978-1-56592-642-4 |access-date=8 May 2018}}</ref>
*Identification of changes: Some filesystems have an [[archive bit]] for each file that says it was recently changed. Some backup software looks at the date of the file and compares it with the last backup to determine whether the file was changed.
*[[Versioning file system]]: A versioning filesystem tracks all changes to a file. The [[NILFS]] versioning filesystem for Linux is an example.<ref name="NILFSHome">{{cite web |title=NILFS Home |url=https://nilfs.sourceforge.io/en/ |website=NILFS Continuous Snapshotting System |publisher=NILFS Community |access-date=22 August 2019 |date=2019}}</ref>