2014-04-02 08:29:34 +00:00
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btrfstune(8)
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============
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NAME
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----
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btrfstune - tune various btrfs filesystem parameters
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SYNOPSIS
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--------
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2014-05-19 15:49:35 +00:00
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*btrfstune* [options] <dev> [<dev>...]
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2014-04-02 08:29:34 +00:00
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DESCRIPTION
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-----------
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2014-05-19 15:49:35 +00:00
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*btrfstune* is used to tune various btrfs filesystem parameters,you can
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2014-04-02 08:29:34 +00:00
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enable/disable some extended features for btrfs.
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OPTIONS
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-------
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-S <value>::
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2014-05-21 08:03:57 +00:00
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Updates the seeding value.
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A positive value will enable seeding, zero will disable seeding, negtive is not allowed.
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Enable seeding forces a fs readonly so that you can use it to build other filesystems.
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2014-04-02 08:29:34 +00:00
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-r::
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Enable extended inode refs.
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-x::
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Enable skinny metadata extent refs.
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2014-07-07 01:54:53 +00:00
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-f::
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2015-05-15 06:28:26 +00:00
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Allow dangerous changes, e.g. clear the seeding flag or change fsid. Make sure
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that you are aware of the dangers.
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-u::
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Change fsid to a random generated UUID or continue previous change operation in
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case it was interrupted with the original UUID.
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-U <UUID>::
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Change fsid to <UUID>.
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+
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The <UUID> should be a 36 bytes string in `printf`(3) format
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"%08x-%04x-%04x-%04x-%012x".
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If there is a previous unfinished fsid change, it will only continue if the
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<UUID> matches the unfinished one.
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WARNING: Cancelling or interrupting a UUID change operation will make the
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filesystem temporarily unmountable. To fix it, rerun 'btrfstune -u' to restore
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the UUID and wait it complete.
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2014-04-02 08:29:34 +00:00
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2014-07-07 01:54:53 +00:00
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When mounting the new device, btrfs will check whether the seeding flag is set
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when try to open seeding device. If the user clears the seeding flag of the
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seeding device, the new device will not be mountable. Even setting the seeding
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flag back will not fix this problem, because the generation will be changed at
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that time. Clear the seeding flag may damage the new filesystem.
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2014-04-02 08:29:34 +00:00
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EXIT STATUS
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-----------
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2014-05-19 15:49:35 +00:00
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*btrfstune* will return 0 if no error happened.
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2014-04-02 08:29:34 +00:00
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If any problems happened, 1 will be returned.
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SEE ALSO
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--------
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`mkfs.btrfs`(8)
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