By Dave Simpson
This month, IBM delivered virtualization and storage services on Cisco's MDS 9000 line of fabric switches and directors. IBM ported its TotalStorage SAN Volume Controller (SVC) software to Cisco's Caching Services Module (CSM), a specialized line card that goes into MDS 9216 switches or 9500 series directors. The two companies claim that the integration project has been in development for two years.
MDS switches with the integrated SVC will be sold by IBM, which will also provide service and support.
The integration of the SVC into the 9000 series switches is an early step in the trend toward fabric-based applications (e.g., hosting storage applications on switches/directors, as opposed to host servers or disk arrays). Other leading storage area network (SAN) switch vendors, including Brocade and McData, have similar projects underway.
Although fabric-based applications aren't expected to take off until the second half of next year, end-user interest is running high, according to a survey of InfoStor readers (see pie chart on p. 1).
IBM's SVC enables applications such as volume management, provisioning, data replication, and point-in-time copies, giving users a single point of control and management across multiple storage subsystems. Other potential advantages include better capacity utilization and the elimination of planned downtime via non-disruptive software upgrades.
However, SVC software integrated on Cisco's CSM does not yet provide true heterogeneous storage pooling because it currently works only with IBM's FAStT and Enterprise Storage Server disk arrays. (The SVC implemented as a stand-alone appliance does support disk arrays from Hitachi Data Systems and Hewlett-Packard, in addition to IBM arrays.)
The stand-alone version of IBM's SVC started shipping in July and is less expensive than an SVC embedded in Cisco's MDS switches. Pricing for the SVC software on Cisco's CSM starts at $112,000 with support for up to 2TB of (IBM) disk capacity, two CSM modules, and SVC software.
According to Robert Wofford, worldwide product marketing manager in IBM's Storage Software division, the main reason for using the SVC integrated in a switch (as opposed to a stand-alone appliance) is that you have one less device on the SAN and you can take advantage of Cisco switch features such as Virtual SANs (VSANs).
Cisco's CSM includes two independent nodes for IBM's software, 8GB of cache memory, hot-swappability, and full redundancy. Implementation of IBM's SVC in Cisco's 9216 fabric switch would require two switches for clustered redundancy. (IBM's SVC is Linux-based clustered software.)
At the Storage Networking World conference in October, Brocade demonstrated a number of applications (from Alacritus, Incipient, Kashya, and other software vendors) on its SilkWorm Fabric Application Platform switch.