Hitachi’s Answer to Storage Virtualization Requirements
by Hu Yoshida on May 17, 2010
Five Requirements for Storage Virtualization
In my previous blog, I identified the following requirements for Storage Virtualization. The first two requirements were already identified by SNIA in 2001. The additional three requirements are addressed by Hitachi in our implementation of Storage virtualization in the USP V/VM. These five requirements are:
1. Application, server, and network Independent management of storage infrastructure
2. Enhance existing storage assets with the latest enterprise storage functions
3. Safe multi-tenancy to leverage shared storage resources across multiple applications
4. Transparency to provide applications with the ability to track their Service level objectives
5. Scalability to meet growing peak demands
Application and Network Independent Management of Storage Infrastructure
The purpose of Storage virtualization is to abstract the management of storage so that changes can be made to storage systems without interruption to the application, server, or network that it is connected to. Hitachi is the only storage vendor that meets these criteria since it has implemented storage virtualization at the storage controller level in the USP V/VM storage system. External storage systems can connect to the USP V/VM through standard FC storage ports. Software in the USP V/VM accesses the existing LUNs in the external storage through these FC connections and presents them through the USP V/VM as though they were USP V/VM LUNS. From then on the host systems attached to the USP V/VM see only the volumes presented by the USP V/VM and the management of the external and internal storage is abstracted and managed independently of the network, the server, and the application.
Enhance Existing Storage Assets with the Latest Enterprise Storage Functions
The USP V/VM is an enterprise storage system with a full complement of tools to do non disruptive moves, copies, migrations, replication, tiering, and dynamic provisioning across internal and external storage. A commodity storage system can inherit these enterprise features simply by connecting behind a USP V/VM. Since the USP V/VM has a large global cache with multiple active paths for load balancing, modular two controller storage systems often see as much as a 30% improvement in throughput when attached to the USP V/VM. The virtualization provided by the USP V/VM can enhance existing storage assets with the latest enterprise capabilities.
Safe Multi-tenancy To Leverage Shared Storage Resources Across Multiple Applications
One of the benefits of storage virtualization is the ability to reduce costs by sharing common resources like storage ports, cache, and disk. However, sharing storage resources raises the risk of data leakage or contention between the multiple storage users or tenants of the virtualized storage systems. The USP V/VM addresses this at different levels. At the host port level, the ports are virtualized into 256 virtual ports and each virtual port can be set to a different server mode (Windows, HP, Solaris, AIX, etc). Each virtual port can also have its own LUN address space which insures save multi-tenancy of the storage ports and LUN images. The next level is at the cache where the cache can be partitioned into 32 dynamic cache partitions. This can prevent a very fast processor like a mainframe from dominating the cache over slower processors and impact their Quality of service. Dynamic tiers of storage and Dynamic Provisioning Pools can also be defined to enable different performance levels for different application requirements.
Transparency to provide applications with the ability to track their Service level objectives
Applications may not trust their data to a virtual pool of shared storage resources without the ability to monitor their service levelobjective, and the health of the physical resources that actually support their storage. This transparency can be provided through the Hitachi Command portal which provides a dashboard with a business view into the shared storage resources that are used by that business or application. The Hitachi Command Portal is part of the Hitachi Storage Command Suite of products which include Device Manager, Global Link Manager, Tuning Manager, Tiered Storage Manager, and Replication Manager. The Command Portal sits on top of these infrastructure management tools, gathers and correlates their information to the application and presents a dashboard of this information through a portal.
One panel on the dashboard show the status of the Service Level Objective, another shows the actual storage allocation, another shows the subsystem health, and the last panel shows the storage allocation trend. The above example provides information for the business unit “Exchange EMEA Corp-Production”
Scalability to meet growing peak demands
Any storage virtualization solution must be able to scale to support the peak demands of the application users of the virtual storage. The virtualization engine must be able to scale up with multiple processors that can be tightly coupled through a large global cache. The Hitachi Virtualization engine is the USP V which can scale up to 128 processors which are tightly coupled through a large 512 GB cache, and support as much as 247 PB of virtual storage capacity. A loose coupling of single storage virtualization processors will not be able to scale to meet the increasing demand for storage resources that are being driven by large virtualization servers that currently run 20 or more server platforms on one powerful multi core server.
It is not enough to simply provide a virtual storage image that can enable the physical storage to be managed separately from the application, server, and network layers. A complete storage virtualization solution must be able to provide enhancements to external storage so that the external storage itself can be commoditized. It must provide a safe multi-tenant virtual environment where multiple users can share the common pool of virtualized storage resources without fear of data leakage or impact from the behavior of other applications in the pool. There should be a simple tool that enables a user to monitor the performance of his Service Level Objective, the health of the physical resources behind the virtualization, as well as his trend line for utilization. And finally the solution must be able to scale to meet the increasing performance and capacity demand of data hungry applications.
Today’s Buzz word is Virtualization, be it Compute, Storage or Network. Keeping in mind todays comodity CPU power and Most of the Server virtualization vendors offer Virtualization of entire Data Center Infrastructure (Compute, Network and Storage). Do we still need virtualization at different component level?.
Here are some of the challenges I feel that pose to Storage Virtualization
One can do live migration of data between different storage teirs or protocol using Server virtualization layer today.The cost of doing at Server level is far less than to do the same task at Storage level.
Using storage we are restricted to LUN level, whereas in Server virtualization we have got VM as files residing inside the datastore/LUNs.
Server Virtualization vendors do offer Thin Provisioning also, which is again one more reason, to have all these features at Server virtualization level.
Once I have all these features I Manage everthing from single pane of glass effectively.
Similar scenario pose for network too..
What is your View on this?