Methods and systems for validating accessibility and currency of replicated data

• US 7,702,667 B2
• Filed: 09/27/2006
• Issued: 04/20/2010
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Kessel, Omri, Yahalom, Raphael, Levy, Assaf, Alon, Roee
• Primary Examiner(s): Cottingham; John R
• Assistant Examiner(s): Khakhar; Nirav K
• Application Number:
  US11/529,748
• Publication Number:
  US 20070088763A1
• Time in Patent Office: 1,301 Days
• Field of Search: None
• US Class Current: 707/611
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• CPC Class Codes: G06F 11/2069 Management of state, configuration or failover
• CPC Class Codes: G06F 11/2071 using a plurality of controllers
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes

Abstract

Systems and processes for determining and validating accessibility and currency, i.e., the actual status, of data replicated in a networked environment are disclosed. According to the disclosed process, a replicated-data policy for replicating data is defined, and access paths between network devices or between applications running on the network devices are monitored, for example, by a replicated-data monitor. Also monitored are the data replication activities in the network. The currency, i.e., timeliness, and accessibility of a replica by a network device is then compared with the requirements in the replicated-data policy and discrepancies with the replicated-data policy are identified, optionally accompanied by a notification.

Claims

1. A process for validating replicated data residing on network devices in a network, comprising:

defining a replicated-data policy for replicating data in the network wherein the replicated-data policy specifies at least a recovery point objective for a set of replicas in the network, wherein the recovery point objective specifies at least a maximum recovery point age of a replica;

monitoring access paths and access path attributes between at least one of network devices and applications running on the network devices, said access paths defining end-to-end communication connectivity between the at least one of network devices and applications;

monitoring data replication activities in the network wherein monitoring data replication activities includes monitoring at least one of a copy start, a copy complete, a synch, a split, a source data volume, a target data volume, and a time of replication;

comparing currency and accessibility of a set of replicas with the requirements in the replicated-data policy to identify discrepancies with the replicated-data policy wherein comparing the currency includes comparing a computed recovery point age of a replica in a set of replicas with the recovery point objective specified in the replicated-data policy and comparing the accessibility of the set of replicas includes comparing a set of access paths associated with the set of replicas to an accessibility requirement specified in the replicated-data policy, thereby validating the replicated data residing in the network, wherein identifying discrepancies includes identifying at least one of currency violation, missing access path, unauthorized access path, and path attribute violation; and

providing a violation notification if a discrepancy is identified.

2. The process of claim 1, wherein the replicated-data policy further specifies at least one of an access path between a host or application and a replica, a number of replicas in a network, locations of the replicas, and one or more access paths between the replicas.

3. The process of claim 1, wherein the currency of each replica includes a copy status selected from the group consisting of in-synch, snapshot time, and inconsistent.

4. The process of claim 3, wherein each replica is associated with a tag which includes at least one of a source data set name, the copy status, and a time stamp.

5. The process of claim 4, wherein the tag of a replica is updated in response to a copier event.

6. The process of claim 1, wherein comparing accessibility of a replica includes identifying at least one of access path to a local host, access path to a remote host, a disaster recovery access path, and an access path to a data copier, said access path conforming to access path attributes defined in an access path policy.

7. The process of claim 6, wherein the access path attributes include at least one of level of end-to-end access path redundancy, number of intermediate components, performance, security, interoperability, sharability, and capacity.

8. The process of claim 1, wherein the violation notification includes at least one of e-mail, SNMP, violation type, affected hosts, time of copy start, and root cause event.

9. The process of claim 1, further including comparing currency and accessibility of replicas of different data volumes and identifying cross-consistency violations.

10. The process of claim 1, further including simulating an effect of future network events and actions on the currency and accessibility of a replica.

11. The process of claim 1, further including generating replication reports which include at least one of applications, replicas and replication properties;

events and impact on replication properties;

replication violations and time to correct them; and

replication resource utilization over time.

12. The process of claim 1, wherein computing the recovery point age of a replica involves deriving a new timestamp for that replica based on a source data set timestamp and a status for each copy event in which the replica is a destination data set.

13. The process of claim 1, wherein computing the associated access path and access path attributes involves constructing an abstract graph representation of the network topology such that each node in the graph represents an application, data set, or a replica, and each edge represents an information flow capability between two nodes, wherein the information flow capability is determined by node configurations and a physical communication link between the two nodes, and determining that the information flow capabilities and attributes between any two nodes are consistent with these specified in the replicated-data policy.

14. The process of claim 1, wherein the set of replicas comprises at least a first replica and a second replica.

15. The process of claim 14, wherein the first replica and the second replica have different currency.

16. The process of claim 14, wherein the first replica and second replica have different accessibility.

17. A replication-data validation management system, comprising:

memory, configured to store a replicated-data policy for replicating data in a network wherein the replicated-data policy specifies at least a recovery point objective for replicas in a set of replicas in the network, wherein the recovery point objective specifies at least a maximum recovery point age of a replica;

a network interface, communicably coupled to the network;

a replication-data validation manager, electronically connected to the memory and to the network interface, configured to;

monitor access path, using the network interface, between at least one of network devices and applications running on the network devices, said access paths defining end-to-end communication connectivity between the at least one of the network devices and applications,

monitor data replication activities in the network, using the network interface, wherein monitoring data replication activities includes monitoring at least one of a copy start, a copy complete, a synch, a split, a source data volume, a target data volume, and a time of replication,

compare currency and accessibility of a set of replicas with the requirements in the replicated-data policy to identify discrepancies with the replicated-data policy, wherein the replicated-data policy is retrieved from the memory, comparing the currency includes comparing a computed recovery point age of a replica in a set of replicas with the recovery point objective specified in the replicated-data policy and comparing the accessibility of the set of replicas includes comparing a set of access paths associated with the set of replicas to an accessibility requirement specified in the replicated-data policy wherein identifying discrepancies includes identifying at least one of currency violation. missing access path, unauthorized access path, and path attribute violation; and

provide a violation notification if a discrepancy is identified.

18. The system of claim 17, wherein computing the recovery point age of a replica involves deriving a new timestamp for that replica based on a source data set timestamp and a status for each copy event in which the replica is a destination data set.

19. The system of claim 17, wherein computing the associated access path and access path attributes involves constructing an abstract graph representation of the network topology such that each node in the graph represents an application, data set, or a replica, and each edge represents an information flow capability between two nodes, wherein the information flow capability is determined by node configurations and a physical communication link between the two nodes, and determining that the information flow capabilities and attributes between any two nodes are consistent with these specified in the replicated-data policy.

20. The system of claim 17, wherein the set of replicas comprises at least a first replica and a second replica.

21. The system of claim 20, wherein the first replica and the second replica have different currency.

22. The system of claim 20, wherein the first replica and second replica have different accessibility.