On Tue, Dec 8, 2020 at 11:14 AM Garry T. Williams <gtwilliams@xxxxxxxxx> wrote: > > On Tuesday, December 8, 2020 1:02:19 PM EST Sreyan Chakravarty wrote: > > How would you verify if a file is CoW in BTRFS? > > It's not btrfs-specific, but use the lsattr(1) command. E.g., > > garry@gtw$ lsattr .local/share/akonadi/db_data/ibdata1 > ---------------C---- .local/share/akonadi/db_data/ibdata1 > garry@gtw$ Small clarification. 'chattr +C' to set the C file attribute is 'nodatacow'. Since Btrfs is cow by default, it's generally OK to assume cow unless this attribute is set. But there's a rather uncommon and not highly recommended mount option too: nodatacow. This does not set C attribute everywhere, but all the files written while this mount option is used are nodatacow and will always be nodatacow. Note that nodatacow (how ever you enable it) also means nodatasum, i.e. no checksumming for data, and no compression. Also, btrfs metadata (the file system itself) is always cow. It can't be disabled. -- Chris Murphy _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
