Dynamic shared journal
A system is provided that includes multiple different consistency groups, a respective thin journal included in each of the consistency groups, and each thin journal includes a respective thin VMDK, a thin journal space that is shared by all of the consistency groups, and the journal space includes a plurality of journal blocks, and a datastore that stores blocks allocated to the thin journals, and datastore space is dynamically allocated in journal blocks to each of the respective consistency groups.
1. A method, comprising:
gathering information concerning thin journal space usage by each of a plurality of consistency groups, and the thin journal space comprises a plurality of journal blocks;
computing an ideal journal block state for each consistency group;
computing an achievable journal block state for each consistency group; and
computing a transition step from the achievable journal block state to the ideal journal block state.
2. The method as recited in claim 1 , wherein when indicated by the transition step, the thin journal space quotas for one or more of the consistency groups are modified.
3. The method as recited in claim 1 , wherein journal blocks of the thin journal are allocated to each of the consistency groups based on a retention optimization method.
4. The method as recited in claim 1 , wherein the ideal journal block state comprises an allocation of thin journal space to the consistency groups that is adequate to meet a service level agreement requirement.
5. The method as recited in claim 1 , wherein the achievable journal block state comprises an achievable allocation of thin journal space to the consistency groups.
6. The method as recited in claim 1 , further comprising predicting a thin journal space consumption rate based on the gathered information.
7. The method as recited in claim 1 , wherein thin journal space is consumed by a respective thin journal of each of the consistency groups.
8. A non-transitory storage medium having stored therein instructions that are executable by one or more hardware processors to perform operations comprising:
gathering information concerning thin journal space usage by each of a plurality of consistency groups, and the thin journal space comprises a plurality of journal blocks;
computing an ideal journal block state for each consistency group;
computing an achievable journal block state for each consistency group; and
computing a transition step from the achievable journal block state to the ideal journal block state.
9. The non-transitory storage medium as recited in claim 8 , wherein when indicated by the transition step, the thin journal space quotas for one or more of the consistency groups are modified.
10. The non-transitory storage medium as recited in claim 8 , wherein journal blocks of the thin journal are allocated to each of the consistency groups based on a retention optimization method.
11. The non-transitory storage medium as recited in claim 8 , wherein the ideal journal block state comprises an allocation of thin journal space to the consistency groups that is adequate to meet a service level agreement requirement.
12. The non-transitory storage medium as recited in claim 8 , wherein the achievable journal block state comprises an achievable allocation of journal space to the consistency groups.
13. The non-transitory storage medium as recited in claim 8 , further comprising predicting a thin journal space consumption rate based on the gathered information.