Adding appliances to the network to facilitate new applications like virtualization has one major disadvantage - on a busy SAN it creates a bottleneck between servers and their storage targets. Cisco Systems says it has an answer, but customers will have to wait a while for it.
The new feature, called the Cisco MDS 9000 Data Tap Service, will provide a protocol-based interface between the Cisco MDS 9000 SAN switches and third-party storage appliances, allowing these appliances to access servers and storage devices on a SAN without having to be directly in the path of the data.
"These in-band appliances create a bottleneck that compromises availability of data, it's a disruptive process and takes constant reconfiguration to avoid," says Rajeev Bhardwaj, senior product manager for the MDS 9000. He says the Data Tap service "non-intrusively enables appliance applications" by passing the data through a line card on Cisco's switch instead of through the appliance, which only sees a copy of the data.
"It's a back door through which data can pass to storage to perform applications like virtualization without having to put something in the data path," says John Webster, senior analyst and founder of the Data Mobility Group.
Cisco has been working on the Data Tap protocol since the fourth quarter of 2003 but is keeping its go to market strategy under wraps. "The standard requires a lot of testing, qualification and stability first…we have no visibility into when it will be available," says Bhardwaj.
Webster notes that for this service to really take off, the appliance vendors must be onboard and so far Cisco hasn't announced any of these yet. "They will have to make the whole thing work," he says.
On the positive side, Cisco has signed deals with three independent software vendors (ISVs) to stage a technology demonstration of the new software feature at SNW in two weeks time. The three partners in the demo are Pleasanton, Calif.-based Alacritus, a maker of disk-based data protection software; San Jose, Calif.-based Kashya, which makes business continuity software, and Santa Clara, Calif.-based Topio, a data recovery software specialist.
In the meantime, Cisco will continue to enable Vertias and IBM applications directly on the switch. "Data Tap is a second way of deploying applications in the network," says Bhardwaj.
The Cisco MDS 9000 Data Tap Service will be available as a feature on one of the line cards for the Cisco MDS 9000 and for use on any of the modular chassis, namely the Cisco MDS 9216, MDS 9506, and MDS 9509.