MANSFIEL%EMBL.BITNET@wiscvm.wisc.EDU (Niall Mansfield) (06/26/87)
Sun say that if you dump at e.g. level 4, you get all files which changed since the last level 0, 1, 2, or 3. Thus, if you keep on doing level 4's, your dump is getting bigger and bigger, e.g. if the sequence is files changed: C1 C2 C3 C4 C5 C6 C7 ... dump level done: 4 4 4 4 4 4 4 ... where Ci is the set of files changed since the last dump (of any level), then your successive dumps will contain 1st dump: C1 2nd C1 C2 3rd C1 C2 C3 4th C1 C2 C3 C4 etc Now, Eric Foxley (in his book "Unix for Super-Users") says that you dump repeatedly at level 4 you would get 1st dump: C1 2nd C2 3rd C3 4th C4 etc which seems a more truly "incremental" method. Is this a difference between Sun/BSD and the AT&T line? What is the rationale behind it? Thanks, Niall
ht@unisol.UUCP (Haral Tsitsivas) (06/27/87)
In article <8034@brl-adm.ARPA> MANSFIEL%EMBL.BITNET@wiscvm.wisc.EDU (Niall >Mansfield) writes: >Sun say that if you dump at e.g. level 4, you get all files >which changed since the last level 0, 1, 2, or 3. The Sun documentations says the right thing (at least for BSD systems)... >Now, Eric Foxley (in his book "Unix for Super-Users") says >that you dump repeatedly at level 4 you would get >1st dump: C1 >2nd C2 >3rd C3 >4th C4 >which seems a more truly "incremental" method. If you really wanted to do what you say with your example you would do dumps at successively higher levels (i.e. 4, 5, 6, 7, 8, 9). It doesn't really make sense to dump files not dumped since the last time a dump of the same level was done... That would place you in a position of having to keep all your dump tapes (and restore from all of them if you had to) and it would probably brake the logic of most dump schemes. What would you do at level 0 (the full dump)? Dump everything since the last full dump? --Haral Tsitsivas