Limited amounts of physical resources can make large-scale virtual infrastructure deployments challenging. Provisioning dedicated storage space to hundreds of virtual machines can become particularly expensive. To address this VMware vSphere 5.5 provides two sparse storage techniques, namely VMFSparse and SEsparse. Running multiple VMs using sparse delta-disks with a common parent virtual disk brings down the required amount of physical storage making large-scale deployments manageable. SEsparse was introduced in VMware vSphere 5.1 and in vSphere 5.5 became the default virtual disk snapshotting technique for VMDKs greater than 2 TB. Various enhancements were made to SEsparse technology in the vSphere 5.5 release, which makes SEsparse perform mostly on par or better than VMFSsparse formats. In addition dynamic space reclamation confers on SEsparse a significant advantage over VMFSsparse virtual disk formats. This feature makes SEsparse the choice for VMware® Horizon View™ environments where space reclamation is critical due to the large number of tenants sharing the underlying storage.
A recently published paper reports the results from a series of performance studies of SEsparse and VMFsparse using thin virtual disks as baselines. The performance was evaluated using a comprehensive set of Iometer workloads along with workloads from two real world application domains: Big Data Analytics and Virtual Desktop Infrastructure (VDI). Overall, the performance of SEsparse is significantly better than the VMFSsparse format for random write workloads and mostly on par or better for the other analyzed workloads, depending on type.
Read the full performance study, “SEsparse in VMware vSphere 5.5.”