hammer upgrade changes md5 checksum
dillon at apollo.backplane.com
Mon Mar 16 19:15:12 PDT 2009
:Now I upgrade the /slave:
: hammer pfs-upgrade /slave
:and get a different checksum:
: cd /slave
: tar cf - DIR | md5 # 3613c...
:If I downgrade again, I get the same checksum as before (9472f...).
:Hm, just curious why this happens and if this might be a bug?
This is probably because HAMMER treats snapshots differently from
live. The mtime and atime will be locked to the ctime when accessed
from a snapshot. tar does not record atime, but I'm pretty sure it
does record mtime.
A slave is accessed as a snapshot. The snapshot TID is the last synced
TID. A master is accessed live (if no @@<TID> extension is given).
That's the difference.
If you access the master using the slve's last-synced TID you should
get the same md5. This information is available in the pfs-status
<dillon at backplane.com>
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