Method and system for adding redundancy to a continuous data protection system

1 . A method for adding redundancy to a continuous data protection system, comprising the steps of:

taking a snapshot of a primary volume at a specific point in time;

storing the snapshot on a secondary volume;

cloning the snapshot and storing the cloned snapshot on a third volume;

expiring the cloned snapshot.

2 . The method according to claim 1 , wherein the taking step is performed according to a retention policy.

3 . The method according to claim 1 , wherein the cloning step is performed according to a cloning policy.

4 . The method according to claim 3 , wherein the cloning policy is part of a retention policy.

5 . The method according to claim 3 , wherein the cloning policy specifies at least one of: a number of clones to be made, a frequency at which a clone is made, and a time period for retaining a clone.

6 . The method according to claim 5 , wherein the expiring step includes deleting the cloned snapshot at the end of the time period specified in the cloning policy.

7 . The method according to claim 1 , wherein the expiring step includes deleting the cloned snapshot at the same time as the snapshot.

8 . The method according to claim 1 , wherein the expiring step includes deleting the cloned snapshot at a different time than the snapshot.

9 . The method according to claim 1 , wherein the primary volume and the secondary volume are located within a first fault zone and the third volume is located in a second fault zone separate from the first fault zone.

10 . A system for adding redundancy to a continuous data protection system, comprising:

snapshot means for taking a snapshot of a primary volume at a specific point in time;

storing means for storing said snapshot on a secondary volume;

cloning means for cloning said snapshot and storing said cloned snapshot on a third volume;

expiring means for expiring said cloned snapshot.

11 . The system according to claim 10 , wherein said snapshot means performs according to a retention policy.

12 . The system according to claim 10 , wherein said cloning means performs according to a cloning policy.

13 . The system according to claim 12 , wherein said cloning policy is part of a retention policy.

14 . The system according to claim 12 , wherein said cloning policy specifies at least one of: a number of clones to be made, a frequency at which a clone is made, and a time period for retaining a clone.

15 . The system according to claim 14 , wherein said expiring means includes deleting said cloned snapshot at the end of said time period specified in said cloning policy.

16 . The system according to claim 10 , wherein said expiring means includes deleting said cloned snapshot at the same time as said snapshot.

17 . The system according to claim 10 , wherein said expiring means includes deleting said cloned snapshot at a different time than said snapshot.

18 . The system according to claim 10 , wherein said primary volume and said secondary volume are located within a first fault zone and said third volume is located in a second fault zone separate from said first fault zone.

19 . A method for managing a recovery point in a continuous data protection system, comprising the steps of:

setting a retention policy;

taking a snapshot of a primary volume according to the retention policy, the snapshot providing a recovery point on the primary volume;

storing the snapshot on a secondary volume;

expiring the snapshot according to the retention policy;

setting a cloning policy;

creating a clone of the snapshot according to the cloning policy;

storing the cloned snapshot on a third volume; and

expiring the cloned snapshot according to the cloning policy.

20 . The method according to claim 19 , wherein the cloning policy is part of the retention policy.

21 . The method according to claim 19 , wherein the cloned snapshot is expired at the same time as the snapshot.

22 . The method according to claim 19 , wherein the cloned snapshot is expired at a different time than the snapshot.

23 . A system for managing a recovery point in a continuous data protection system, comprising:

first policy means;

snapshot means for taking a snapshot of a primary volume, said first policy means controlling said snapshot means;

first storing means for storing said snapshot on a secondary volume;

first expiring means for expiring said snapshot, said first policy means controlling said first expiring means;

second policy means;

cloning means for creating a clone of said snapshot, said second policy means controlling said cloning means;

second storing means for storing said cloned snapshot on a third volume; and

second expiring means for expiring said cloned snapshot, said second policy means controlling said second expiring means.

24 . The system according to claim 23 , wherein:

said first policy means includes a retention policy; and

said second policy means includes a cloning policy.

25 . The system according to claim 23 , wherein said second policy means is part of said first policy means.

26 . A system for continuous data protection, comprising:

a host computer;

a first volume connected to said host computer, said first volume containing data to be protected;

a first data protection system connected to said host computer;

a second volume connected to said first data protection system, said second volume being a protected version of said first volume;

a second data protection system communicating with said first data protection system; and

a third volume connected to said second data protection system, said third volume being a copy of said second volume.

27 . The system according to claim 26 , wherein said first data protection system and said second data protection system communicate asynchronously.

28 . The system according to claim 26 , wherein said second data protection system and said third volume are located in a fault zone with said first data protection system and said second volume.

29 . The system according to claim 26 , wherein said second data protection system and said third volume are located in a fault zone separate from said first data protection system and said second volume.

30 . The system according to claim 26 , further comprising:

a third data protection system communicating with said second data protection system; and

a fourth volume connected to said third data protection system, said fourth volume being a copy of said third volume.

31 . The system according to claim 30 , wherein

said second data protection system communications with said first data protection system synchronously, whereby said third volume is a current copy of said second volume; and

said third data protection system communicates with said second data protection asynchronously.

32 . The system according to claim 30 , wherein

said second data protection system and said third volume are located in a first fault zone with said first data protection system and said second volume; and

said third data protection system and said fourth volume are located in a second fault zone, said second fault zone being separate from said first fault zone.

33 . The system according to claim 30 , wherein

said first data protection system and said second volume are located in a first fault zone;

said second data protection system and said third volume are located in a second fault zone, said second fault zone being separate from said first fault zone; and

said third data protection system and said fourth volume are located in a third fault zone, said third fault zone being separate from said first fault zone and said second fault zone.