Btrfs/it

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Btrfs filesystem

Introduzione

Btrfs è un filesystem copy on write per Linux, teso ad implementare delle caratteristiche avenzate pur concentrandosi sulla tolleranza agli errori, la riparazione degli stessi e la semplicità di amministrazione. Fornisce la possibilità di configurare gruppi di dispositivi, delle funzionalità simili al RAID, la rapida creazione di snapshot e il checksum di dati e metadati. Inizialmente sviluppato da Oracle, Btrfs è stato rilasciato sotto licenza GPL ed è aperto al contributo di chiunque.

Informazioni più dettagliate si possono trovare sulla Homepage di Btrfs.

Scopo di questa pagina

Questa pagina fornisce informazioni specifiche al supporto di Btrfs su Fedora.

Stability status and support

Fedora maintains fairly recent kernels and btrfs-progs that are typically identical to upstream. The best resources are the Btrfs Wiki and mailing list.

The current stability status page.

Mailing list information.

Btrfs support in Fedora

• Btrfs has been available as an installation time option as early as Fedora 11.
• All Fedora products include Btrfs support in the kernel, and user space tools are installed by default.

Installing

• The Fedora installer, Anaconda, provides Btrfs as an option in Manual Partitioning.
• The Btrfs partition scheme preset creates an ext4 /boot, swap, and a Btrfs pool. Two subvolumes, root and home, are created from that pool and mounted at / and /home respectively.
• Additional mount points using Btrfs will also have corresponding subvolumes created based on the Name field. Subvolumes do not have a size, so the Desired Capacity field when creating new mount points is ignored and can be left blank.

Conversions from Ext3/Ext4 volumes to Btrfs (and back!)

Although Btrfs does not need LVM, if you already are using it then converting your volume does not remove LVM.

• The convert code has been rewritten as of btrfs-progs 4.6, it's advised to avoid older versions.
• Check the upstream Btrfs changelog for the most recent recommended version of btrfs-progs.
• The most recent recommended btrf-progs may not be in the Fedora repository version you're using, it can be found in Koji.
• Btrfs Wiki has more information on conversion and rollback.

Frequently Asked Question(s)

• Why use (or not use) Btrfs?
  • Data integrity: detection of corrupt metadata and data, automatic repair when there's redundancy.
  • Fast snapshot creation, btrfs send/receive snapshots for replicating and backup.
  • Online resizing and addition/removal of disks.
  • Filesystem based RAID 0/1/10/5/6. See the Btrfs status page for feature stability. Some features are considered experimental!
  • 'btrfs check' a.k.a. btrfsck, is safe. However, while --repair should be safe, it comes with many warnings. See 'man btrfs check'.
  • If a Btrfs volume fails to mount, try 'mount -o usebackuproot'. If that also fails report the issue on the Btrfs mailing list, including the output from 'btrfs check' without --repair.