merge(8)merge(8)NAMEmerge - merge incremental dumps onto full dumps for restore
SYNOPSISmerge <output file> <full dump> <incremental dump>
DESCRIPTIONmerge is a utility that allows one to apply incremental dumps to a full
dump and produce a new full dump which reflects a later state of the
volume. The new dump can then be used to restore the volume, or can be
merged with other incrementals.
An incremental or full dump reflects the state of the volume at the
time it was dumped. Full dumps can be restored so that a user may
access an older state of a volume. Incremental dumps do not necessarily
have sufficient information to be restored. For instance, all the
vnodes in the dump may not be present. The merging process allows a
full image of a state that was only incrementally dumped to be
restored.
Currently incrementals apply to the last successful full dump that was
done. As an example, say full dumps for a volume are done on Sundays,
with incrementals being taken the rest of the week. If an administrator
wishes to restore a volume to Wednesdays state, he would have to fetch
the full dumpfile from Sunday and the incremental dumpfile for Wednes‐
day. Once these are present, the administrator would use the merge pro‐
gram to create a new updated full dump for Wednesdays state, and
restore it to the server (using volutil(8) restore).
Information in the dump header is used to place a total ordering on the
dumps. This way incrementals can only be applied to the dump with
repect to which they were taken. In addition, incrementals cannot be
applied to other incrementals, and the dumps to be merged must have
been created from the same volume replica. The merge program checks
these things, and reports failures if they are violated.
SEE ALSO
volutil (8), restore (1)
AUTHOR
David C. Steere, 1991, created
merge(8)
