Matthew Dillon dillon at
Tue Sep 15 17:59:28 PDT 2009

:Ok the kernel is 1 week old. I update the kernel and userland on every
:I guess undo will be recompiled automatically when I update the userland?
:> =A0 =A0snapshots 0d 1m ? =A0You have snapshots disabled and the retention=
: is
:> =A0 =A0set to 1 minute ?
:I did it to disaable snapshot and remove the first snapshot.
:Will that affect the history of file?

    It controls how pruning works.  You basically told it to throw away
    all history over 1 minute old.  This might or might not be responsible
    for undo -i reporting virtually no history for the file, depending on
    when the hammer cleanup maintainance task was last run.

    Normally you set it to something like 'snapshots 1d 60d'.

    With recent kernels you can also tell HAMMER specifically how much
    fine-grained history you want to retain by setting a PFS config
    variable.  man hammer and read up on the 'prune-min' PFS config
    specification.  With this specification you can for example tell
    the pruner to save snapshots on a daily basis and retain history for
    60 days but to also retain fine-grained history for e.g. 3 days.
    Normally any fine-grained history after the first snapshot is deleted
    by the prune operation.


    The easiest way to remove a snapshot is to just remove the softlink.
    the daily hammer maintainance will then prune out any records related
    to that snapshot.

					Matthew Dillon 
					<dillon at>

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