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ME4 Series features
7 Dell EMC PowerVault ME4 Series and VMware vSphere | 3922-BP-VM
2 ME4 Series features
Although the ME4 Series is targeted at the entry level of the SAN market, it contains many advanced and
enterprise-class features detailed in the following sections. It is recommended that both the storage
administrator and the VMware administrator have a solid understanding of how these storage feature can
benefit the vSphere environment prior to deployment.
Note: The ME4 Series array uses the term Virtual Volume, which is not associated with the VMware vSphere
Virtual Volumes™ feature.
2.1 Virtual and linear storage
ME4 Series arrays use two storage technologies that share a common user interface: the virtual method and
the linear method.
The linear method maps logical host requests directly to physical storage. In some cases, the mapping is one-
to-one, while in most cases, the mapping is across groups of physical storage devices, or slices of them.
While the linear method of mapping is highly efficient, it lacks flexibility. This makes it difficult to alter the
physical layout after it is established.
The virtual method maps logical storage requests to physical storage (disks) through a layer of virtualization,
such that logical host I/O requests are first mapped onto pages of storage and then each page is mapped
onto physical storage. Within each page, the mapping is linear, but there is no direct relationship between
adjacent logical pages and their physical storage. A page is a range of contiguous logical block addresses
(LBAs) in a disk group, which is one of up to 16 RAID sets that are grouped into a pool. Thus, a virtual volume
as seen by a host represents a portion of storage in a pool. Multiple virtual volumes can be created in a pool,
sharing its resources. This allows for a high level of flexibility, and the most efficient use of available physical
resources.
Some advantages of using virtual storage include the following:
• It allows performance to scale as the number of disks in the pool increases.
• It virtualizes physical storage, allowing volumes to share available resources in a highly efficient way.
• It allows a volume to be comprised of more than 16 disks.
Virtual storage provides the foundation for data-management features such as thin provisioning, automated
tiered storage, read cache, and the quick disk rebuild feature. Because these storage features are valuable in
most environments, virtual storage is recommended when deploying VMware vSphere environments. Linear
storage pools are most suited to sequential workloads such as video archiving.
2.2 Enhancing performance with minimal SSDs
While the cost of SSDs continues to drop, there is still a significant price gap between SSDs and traditional
spinning HDDs. Not all environments require the performance of an all-flash ME4 Series array, however, ME4
Series arrays can utilize a small number of SSD drives to gain a significant performance increase. Both the
automated tiered storage and read flash cache features of the ME4 Series array use a small number of SSDs
to provide a significant performance boost to a traditional low-cost, all-HDD SAN solution.