ViPR SRM for VPLEX?

VPLEX is EMC’s premier storage virtualization solution.  While VPLEX greatly simplifies everyday storage management, storage virtualization has presented storage administrators with new challenges in areas such as reporting, performance troubleshooting and chargeback.  In ViPR SRM v3.5, new capabilities enable you to peer under the virtualization layer to understand what’s actually going on in a virtualized environment.  In a VPLEX environment, ViPR SRM enables a storage administrator to understand how storage capacity is being used, and who is using it;  to understand end-to-end relationships from host to storage; and to verify that VPLEX is configured according to best practices.

For example, a challenge for a storage administrator is to understand, overall, how storage is being used—how much for traditional block or file, how much is virtualized, how much is free, and so forth. New to v3.5, a unified enterprise capacity dashboard shows  total storage capacity for the environment in one place, and how it is used.  The dashboard includes a view of usable capacity (top middle view), with a bar indicating how much is used for virtual storage.  Note that the virtual storage is actually based on physical block storage; so ViPR SRM carefully ensures that this block storage is not counted twice in the enterprise dashboard.

Many problems in storage reporting and management require correlating the end-to-end relationships between host, SAN, and storage.  Storage virtualization makes this correlation much more difficult.  In a traditional non-virtual environment, a LUN on a physical array is presented directly to the host (or, in the case of VMWare, to the ESX server).  VPLEX, in contrast, presents to the host a virtual volume that has several layers of indirection between it and the array LUN; layers which could include such factors as clustering or partitioning of the array LUNs to provide the actual storage behind the virtual volume.

ViPR SRM v3.5 has added the ability to “reverse engineer” these intermediate layers and correctly map host devices to array storage LUNs.  One case where this ability is essential is chargeback.  In order to allocate storage costs correctly among business units and applications, the storage administrator must determine how much storage, and what storage service level, is being used by each production host.  Service levels are typically determined at the LUN level, based on the actual physical disk types used by the LUN; so ViPR SRM’s ability to map virtual volumes to LUNs enables accurate chargeback in a VPLEX environment.

Another place where the storage administrator needs to understand end-to-end relationships is performance troubleshooting.  Performance problems exhibited by an application can sometimes be caused by a bottleneck in the SAN or array. The storage administrator will need to trace the host dependencies back through the virtualization layer through the SAN to the physical storage.   In order to show those physical links and dependencies, ViPR SRM incorporates VPLEX into the topology views for hosts, VMs and arrays, as well as the VPLEX-specific views.

Because topologies can fan out rapidly and become very complex, ViPR SRM also provides the more focused Path Details views. In these, the user can trace back from a host device or datastore all the way to the storage LUN.  In ViPR SRM v3.5, the user can now do this even with an intermediate VPLEX layer.  Path Details will show all the intermediate VPLEX constructs, such as storage LUNs, groups and extents in the path from the host to the array.

When you pair this with SRM’s ability to trace relationships within VMWare, this can be a very powerful tool for troubleshooting performance, and other uses that require understanding logical to physical dependencies. For example, in the table below, we can map a device in a virtual machine via the datastore and ESX host device, directly to the associated VPLEX storage LUN; and from there to two VPLEX extents, which physically reside on two LUNs in two distinct VNX systems.

Of course, ViPR SRM allows you to closely examine a specific VPLEX system, in addition to the end-to-end and enterprise views described previously.  In v3.5, topology and path details can be viewed in the context of the individual VPLEX system.

In short, ViPR SRM’s ability to peel back virtualization layers, and correlate hosts, switches and physical storage, make it a very powerful tool for the storage administrator in modern storage environments.