Mass storage system and methods of controlling resources thereof
A storage system and a method for managing a memory capable of storing metadata related to logical volume sets, are disclosed. A memory quota is assigned to a metadata related to a logical volume set. The size of a memory currently consumed by the metadata is monitored. Upon exceeding a threshold by the size of the monitored memory, at least one restraining action related to memory consumption by the metadata is applied.
1. A method of managing metadata for managing a logical volume set out of multiple logical volume sets configured in a storage system, the method comprising:
a. monitoring by a memory monitor of the storage system a size of the metadata, the logical volume set comprises at least one logical volume and at least one snapshot; and
b. upon detecting that said size of the metadata has exceeded a threshold related to a memory quota assigned to said metadata, restraining by a volume manager of the storage system at least one service related to data stored in the logical volume set and affects said size of said metadata.
2. The method of claim 1 , wherein the method is provided for all logical volume sets configured in the storage system.
3. The method of claim 1 , wherein said metadata comprises a data-structure capable of mapping between virtual storage addresses and physical storage addresses allocated to said logical volume set.
4. The method of claim 1 , wherein said logical volume set includes a plurality of logical volumes associated with a specific owner entity.
5. The method of claim 1 comprising assigning said memory quota in accordance with a quality of service guaranteed to an owner entity of said logical volume set.
6. The method of claim 1 comprising assigning the memory quota to said metadata in accordance with at least one aspect selected from: a type of volume provisioning technique applied on said logical volume set and a class of service assigned to said logical volume set.
7. The method of claim 1 , wherein said at least one service is selected among services in accordance with a classification of said logical volume set.
8. The method of claim 1 , wherein one or more thresholds related to said memory quota are characterized by respective severity levels, and wherein said at least one service is selected among services, in accordance with a severity level of a threshold out of the one or more thresholds related to said memory quota that is being exceeded.
9. The method of claim 1 further comprising
applying at least one action related to reducing the size of said metadata when detecting that the size of said metadata has exceeded a second threshold.
10. The method of claim 1 wherein said at least one service being restrained is selected from a group consisting of:
a. creation of new snapshots related to said logical volume set;
b. data writings to writable snapshots related to said logical volume set; and
c. data writings to the at least one volume comprised in said logical volume set, in case said at least one logical volume is associated with at least one snapshot.
11. The method of claim 9 , wherein said at least one action is selected from a group consisting of:
a. deleting one or more snapshots associated with said logical volume set;
b. enabling execution of a defragmentation process that enables reducing the size of said metadata;
c. compressing cold areas related to said metadata; and
d. paging out cold areas related to said metadata.
12. A method of managing metadata for managing a logical volume set out of logical volume sets configured in a the storage system, the method comprising:
a. monitoring by a memory monitor of the storage system a size of the metadata, wherein the logical volume set comprises at least one logical volume and at least one snapshot; and
b. upon detecting that said size of said metadata has exceeded a threshold related to a memory quota assigned to said metadata, restricting by a volume manager of the storage system services related to snapshots associated with said logical volume set.
13. A storage system, comprising:
a metadata memory for storing a metadata related to a logical volume set configured in the storage system, the logical volume set comprises at least one logical volume and at least one snapshot;
a memory monitor, operatively coupled to said metadata memory, configured to monitor a size of said metadata and to detect that said size of said metadata has exceeded a threshold related to a memory quota assigned to said metadata; and
a volume manager, operatively coupled to said metadata memory and said memory monitor, the volume manager is configured to restrain at least one service related to data stored in the logical volume set and affects said size of said metadata, upon exceeding the threshold.
14. The storage system of claim 13 , wherein said metadata comprises a data-structure capable of mapping between virtual storage addresses and physical storage addresses allocated to said logical volume set.
15. The storage system of claim 13 , wherein the volume manager is configured to assign said memory quota in accordance with a quality of service guaranteed to an owner entity of said logical volume set.
16. The storage system of claim 13 , wherein said at least one service is selected among services, in accordance with a classification of said logical volume set.
17. The storage system of claim 13 , wherein one or more thresholds related to said memory quota are characterized by respective severity levels, and wherein said at least one service is selected among services in accordance with a severity level of a threshold out of the one or more thresholds that is being exceeded.
18. The storage system of claim 13 , wherein said at least one service being restrained is selected from a group consisting of:
a. creation of new snapshots related to said logical volume set;
b. data writings to writable snapshots related to said logical volume set; and
c. data writings to the at least one volume comprised in said logical volume set, in case said at least one logical volume is associated with at least one snapshot.
19. The storage system of claim 13 , wherein said volume manager is configured to apply at least one action related to reducing the size of said metadata when detecting that the size has exceeded a second threshold, wherein the at least one action is selected from a group consisting of:
a. deleting, in accordance with a predefined rule, one or more snapshots associated with said logical volume set; and
b. enabling execution of a defragmentation process that enables reducing the size of said metadata.
20. A non-transitory computer readable storage medium, that stores program instructions that when executed by a computer, cause the computer to perform:
a. monitoring a size of metadata for managing a logical volume set, the logical volume set comprises at least one logical volume and at least one snapshot; and
b. upon detecting that said size has exceeded a threshold related to a memory quota assigned to said metadata, restraining at least one service related to data stored in the logical volume set and affects said size of said metadata.