Check out this podcast interview to learn how companies with virtual server environments are coping with storage...
challenges. Jeff Boles, senior analyst at Taneja Group in Hopkinton, Mass., talks about the pros and cons of Fibre Channel (FC) storage-area networks (SANs) and iSCSI SANs in virtualized environments.
Q. What type of storage architectures are you finding most common among companies with virtual server environments?
A. Today, 85% of server virtualization environments are being attached to SANs. SANs fall into two categories: the traditional Fibre Channel SAN and a slightly newer iSCSI SAN.
About 55% of the new server virtualization environments out there are being attached to Fibre Channel and about 30% are being attached to iSCSI. Those numbers are definitely on an upswing on the iSCSI side compared to past years.
I think some of the things that have helped iSCSI gain more traction in the server virtualization marketplace – in addition to the traditional iSCSI features or capabilities they excel in like ease of use and scalability, and using a common and familiar network connection – is that now iSCSI products are even more established in the marketplace and end users' sites. Since the Dell [Inc.] acquisition of EqualLogic [Inc.] and the [Hewlett-Packard Co.] acquisition of LeftHand [Networks Inc.], it's quite obvious that a number of these iSCSI products and vendors are here to stay. iSCSI has even more credibility in the marketplace and is obviously much more established now than even just a couple of years ago.
Q. To what degree are you seeing IT shops use storage virtualization products in connection with their virtual server environments?
A. One of the reasons that we see people turning to iSCSI quite often is for some of these storage virtualization capabilities or for some of the benefits that storage virtualization can deliver. So iSCSI often delivers ease of use and more flexibility on the back-end storage infrastructure because it often comes with a virtualization layer built into a homogeneous iSCSI solution.
Outside of the iSCSI realm, server virtualization products are quite often coupled with storage virtualization projects as well. Very often, it's a reactive engagement of a storage virtualization project because when users get into server virtualization initiatives, they rapidly discover that the capacity requirements and performance requirements that hit their back-end SAN drive them to desire more flexibility in their storage infrastructure than they had before.
Q. Can you summarize the benefits and drawbacks of adding that storage abstraction layer in a virtualized server environment?
A. There is a lot of awareness in the industry right now about how storage virtualization can help your virtual server infrastructure by giving you more flexibility, making your storage back end more adaptable to changing server virtualization needs.
The drawbacks to storage virtualization are a little bit stickier, and it comes down to your trust in a vendor and your ability to do due diligence on their capabilities.