Originating Author: Nelson Nahum
SVM 5 is the current generation of the LSI Storage Virtualization product. The idea behind SVM is to enable advanced data services such as storage pooling, thin provisioning, space efficient snapshots, online data migration, and remote replication in existing storage array environments. This allows you to consolidate many different arrays from different vendors into a single “storage system” without the need to replace any hardware. A prerequisite is that the storage array model has been qualified by LSI to work with SVM 5.
In addition to augmenting the storage features of existing arrays, having a storage virtualization layer at the SAN level enables capabilities like remote mirroring with different array types on each side, non-disruptive data migration between devices, and the creation of a consistency group of volumes that span multiple different arrays.
SVM has a split path architecture using an out-of-band metadata server (the SVM) to create and manage the virtualization maps (i.e metadata), and multiple in-band data paths (DPMs) that move data from server to storage as fast as possible in accordance with the virtualization tables provided by the SVM.
SVM 5 runs on a LSI DPM 8400 that has 16 4GB/sec ports and is capable of performing up to 1 Million IOPs per DPM. Although a single pair of DPMs is adequate for most SANs, it is possible to deploy multiple DPMs to scale-out the storage virtualization performance.
One of the key design goals of SVM was to introduce storage virtualization at existing SANs with minimum effort and cost. Usually effort is required to ensure that the SAN and storage arrays are configured to conform to SVM requirements. After that a simple SVM system can be deployed in days, and it is then possible to import LUNs with data into the virtualization environment very quickly. SVM allows the coexistence of non-virtualized and virtualized storage, even within the same array, enabling users to start small and grow the virtualized environment over the time.
SVM is a mature product with more than five years of deployments around the world. Most of SVM users started to virtualize their storage to solve a particular problem (i.e. storage pooling, or remote mirroring or data migration or space efficient snapshots), and over time ended up virtualizing much of the storage environment.
LSI provides SVM though some direct channel partners and through OEM agreements with IT vendors such as HP. The software is licensed on a sliding scale according to the number of terabytes virtualized. HP in particular offers a very strong set of qualified storage arrays and services available in the United States and internationally that provide a "single throat to choke".
Action Item: In today's harsh economic environment, heterogeneous virtualization is a sound strategy for improving the return on existing storage assets. SVM 5 from LSI competes well on heterogeneous virtualization functionality with IBM's SVC, Hitachi's USP VM and EMC's Invista products. LSI's strategy of achieving volume with channel and OEM agreements is sound and provides multiple alternatives for potential customers. Wikibon recommends that products using the SVM technology be strongly considered for inclusion in heterogeneous virtualization RFPs.
Footnotes: 2009 Storage budget cuts - what are your options?