The reliability of data and services hosted on a virtual machine (VM) is a top concern in cloud environments. The Continuous Snapshots can reduce the data loss in case of… Click to show full abstract
The reliability of data and services hosted on a virtual machine (VM) is a top concern in cloud environments. The Continuous Snapshots can reduce the data loss in case of failures and thus is prevailing for protecting long-running systems. However, existing methods suffer from long VM downtime, long snapshot interval and significant performance loss. In this article, we present iConSnap, a system designed to take fine-grained continuous snapshots of virtual machines without compromising VM performance. First, iConSnap adopts the copy-on-write (COW) mechanism to save the memory pages on-demand, and thus decreases the VM downtime to about 200 milliseconds. Second, we extend the idea of COW and propose a lazily incremental approach to save the delta data between two successive snapshots only once, thereby reducing the snapshot duration and snapshot data a lot. Third, we propose a scheduling mechanism to mitigate the VM performance penalty issue. Last, we introduce a method combined of compression and time-aware multi-granularity reclamation strategy to reduce the storage costs without losing performance and availability. We implement iConSnap on QEMU/KVM and evaluate it through a set of experiments. The experimental results show that iConSnap outperforms existing approaches in terms of VM downtime, snapshot duration, storage costs and VM performance.
               
Click one of the above tabs to view related content.