EMC’s VPLEX and VMware - Cloud Computing

Recently, EMC, VMware’s controlling parent, introduced VPLEX as a virtual RAID (redundant array of independent disks or redundant array of inexpensive disks) for a storage area network (SAN) in order to access data anywhere within the private cloud. Wikipedia defines RAID5 as

. . . a technology that provides increased storage reliability through redundancy, combining multiple low-cost, less-reliable disk drive components into a logical unit where all drives in the array are interdependent. The concept was first defined by David A. Patterson, Garth A. Gibson, and Randy Katz at the University of California, Berkeley in 1987 as redundant array of inexpensive disks.

VPLEX extends RAID beyond the datacenter and is storage agnostic. Two unique features of VPLEX are cache coherency and dirty region logs. These facilitate high speed, long distance, and reliable operation. Prior to EMC VPLEX, information mobility was only available through the use of special purpose technologies and specifically designed applications. With VPLEX, you simply carve up storage and present it to the VPLEX; the VPLEX then claims the storage from the back-end and it presents it (makes it available) to your servers.

You can claim storage from one SAN, claim storage from a different SAN that could be in the same data center or at another data center within synchronous distance (meaning that communication speed is very high) and then you can connect the two storages together in a RAID architecture. The servers behind the VPLEX just see this single virtualized storage unit even though it is being presented from multiple sources.

The VPLEX is a hardware and software solution that comes in two configurations, Local and Metro. The Metro configuration extends a storage infrastructure by up to 100 Km. The goal, according to EMC, is to continue to extend this distance in future releases.

VPLEX Local provides local federation across heterogeneous arrays, whereas VPLEX Metro permits two clusters within limited distances to access the same physical Logical Unit Number (LUN). The VPLEX system architecture uses distributed cache coherence, active--active data sharing and scale--out performance, all new technology innovations developed by EMC.

EMS controls VMware, so it is not surprising that VPLEX and VMware interact well together::
The combination of EMC VPLEX and VMware vMotion enables you to effectively distribute applications and their data across multiple hosts over synchronous distances. With Virtual Storage and virtual servers working together over distance, your infrastructure can provide load balancing, real-time remote data access, and improved application protection.

Storage vMotion lets you relocate virtual machine disk files between and across shared storage locations while maintaining continuous service availability and complete transaction integrity.

• Reduce IT costs and improve flexibility with server consolidation
• Decrease downtime and improve reliability with business continuity and disaster recovery
• Increase energy efficiency by running fewer servers and dynamically powering down unused servers with our green IT solutions,

Key VPLEX features include:

• Active and very resilient
• Supports up to 8,000 virtual volumes per VPLEX cluster
• Maximum Logical Unit Number (LUN) size (as tested by EMC) of 32 TB (a LUN is the identifier of a SCSI logical unit, and by extension of a Fibre Channel or iSCSI logical unit)8
• 8 GBS fiber connection recommended between VPLEX devices
• Support maximum latency of 5 ms across locations
• Easiest migration path is through Storage vMotion