Thin Provisioning Storage Interfaces for Block Reclamation
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Solution Overview
Problem
Existing virtualization technologies face storage inefficiencies due to the accumulation of 'stale' data blocks in thinly-provisioned virtual disks and LUNs, where allocated space is not timely reused, leading to reduced storage space optimization benefits.
Innovation Solution
System software interfaces are provided to enable the discovery of thinly-provisioned LUNs and virtual disks, allowing for the deallocation of unused storage blocks through UNMAP commands, ensuring efficient storage space reclamation and reallocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thin provisioning is implemented to dynamically allocate physical storage space, then storage space utilization is improved, but storage efficiency deteriorates due to accumulation of stale data blocks
Solution Approach 1:
The storage system automatically identifies and deallocates stale data blocks through the UNMAP command mechanism without requiring manual intervention. The system self-monitors block allocation status and autonomously reclaims space by issuing deallocation commands to the storage array, enabling continuous optimization of storage efficiency while maintaining high utilization through thin provisioning
Solution Approach 2:
The patent implements a feedback mechanism where the host system continuously monitors the allocation status of storage blocks and receives information about stale blocks from the storage array. This feedback loop enables the system to identify blocks that are no longer in use by virtual machines and trigger UNMAP commands to deallocate them, thereby maintaining storage efficiency while preserving the benefits of thin provisioning
2Productivity
If virtual machines are instantiated with allocated disk space, then virtual machine performance is improved, but physical storage capacity is stressed
Solution Approach 1:
The patent implements dynamic thin provisioning that allows virtual machine disk allocations to be flexible rather than static. Physical storage space is allocated on-demand as virtual machines actually use it, rather than pre-allocating fixed space. This dynamic approach maintains virtual machine performance by ensuring available storage when needed while optimizing physical storage capacity utilization across the entire virtualized environment
Solution Approach 2:
The system changes the provisioning parameter from static pre-allocation to dynamic on-demand allocation. By implementing the UNMAP command mechanism, the system can dynamically adjust the amount of physically allocated space based on actual usage patterns, allowing virtual machine performance to be maintained while significantly improving overall physical storage capacity efficiency
Data Source
AI summary
Interfaces to storage devices that employ storage space optimization technologies, such as thin provisioning, are configured to enable the benefits gained from such technologies to be sustained. Such an interface may be provided in a hypervisor of a virtualized computer system to enable the hypervisor to discover features of a logical unit number (LUN), such as whether or not the LUN is thinly provisioned, and also in a virtual machine (VM) of the virtualized computer system to enable the VM to discover features of a virtual disk, such as whether or not the virtual disk is thinly provisioned. The discovery of these features enables the hypervisor or the VM to instruct the underlying storage device to carry out certain operations such as an operation to deallocate blocks previously allocated to a logical block device, so that the storage device can continue to benefit from storage space optimization technologies implemented therein.