Does the Slave pfs take up more space that the Master?

Matthew Dillon dillon at apollo.backplane.com
Fri Apr 16 09:41:18 PDT 2010


:Hi Matt,
:
:As 'hammer info' directive does, the only way I know to do this would
:be to go through all the PFS until the max (HAMMER_MAX_PFS), if no one
:has come with a better idea or solution.
:
:Actually, this should be pretty straightforward if you just go through
:all the PFS, identify the ones that exist and then you just simply
:perform the cleanup on the @@ link. i.e:
:
:antonioh at smash> hammer cleanup /@@-1:00007
:cleanup /@@-1:00007          - handle PFS #7 using /var/hammer/@@-1:00007
:           snapshots - disabled
:               prune - run
:           rebalance - run..
:             reblock - run....
:              recopy - run....
:
:Dunno tho if this solution would be optimal.
:
:I would like to takeover this activity if no one is interesed.
:
:Cheers,
:Antonio Huete

    I think this is a pretty good solution and it would be great if you
    took over the handling of it!  What I suggest is you start by putting
    in the PFS scan (0-65535), and then later on we can add an ioctl()
    to ask the HAMMER filesystem for the largest PFS id and then just
    limit the scan to that.

    A slightly more hackish but just as optimal approach would be to perform
    an internal silent mirror-read of the PFS control record space (i.e.
    scan them ourselves) and figure out the range from that.  This would
    be nearly instantanious but would also be a bit more complicated.
    My preference would be to add the ioctl() instead.

						-Matt






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