Den 2014-03-16 11:58 skrev Paul Vinkenoog såhär: > > Kjell Rilbe wrote: > > > First day of year: N=0, initial complete backup. > > First day of each month: N=1, will contain all pages changed since first > > day of year. > > First day of each week: N=2, will contain all pages changed since first > > day of month. > > Each day: N=3, will contain all pages changed since first day of week. > > > > If two such days coincide, you still need to run both "colliding" levels > > (lower N first, higher N directly afterwards), or the sequence will be > > broken next day. > > That's not necessary, and the higher level backup will add nothing on > that moment. > > Suppose you make a level-2 backup every Sunday. Then it makes sense to > schedule the level-3 backups daily from Mon-Sat. > > If you want to make a point-in-time restore later, it will involve 4 files > if that point in time is on Mon-Sat, and 3 files if it is on a Sunday. > (And 2 files if it is the first day of the month.) > > All you have to do is determine the most recent backup before the chosen > point in time. If that is a level N, you need N+1 files for the restore > (levels 0-N, each one being the most recent file of that level before > time 'T'). >
My idea was to avoid having to keep track of N for last backup. The script & scheduling would be a bit simpler. And I do realize the N=1 backup right after the N=0 backup will store nothing. It will, however, make it possible to do the N=2 backup next day and have a complete N-chain. Skipping the N=1 backup and go right for N=2 won't work. or am I missing something? Kjell
