-text "
-dss snapshot aging is implemented in terms of intervals. There are
-two command line options related to intervals: the duration of a
-'unit' interval and the number of those unit intervals.
-
-dss removes any snapshots older than the given number of intervals
-times the duration of an unit interval and tries to keep the following
-number of snapshots per interval:
-
- interval number number of snapshots
- ===============================================
- 0 2 ^ (num_intervals - 1)
- 1 2 ^ (num_intervals - 2)
- 2 2 ^ (num_intervals - 3)
- ...
- num_intervals - 2 2
- num_intervals - 1 1
- num_intervals 0
-
-In other words, the oldest snapshot will at most be unit_interval *
-num_intervala old (= 5 days * 4 = 20 days if default values are used).
-Moreover, there are at most 2^num_intervals - 1 snapshots in total
-(i.e. 31 by default). Observe that you have to create at least
-num_intervals snapshots each interval for this to work out. "
-
-option "unit_interval" u