Thu. Jul. 03, 2008
Dell's FlexAddress announcement on Tuesday drew this response by Gary Thome of HP. So what's a poor system admin to do if they want to manage SAN and LAN addresses for their blade systems? I'd suggest they let their accountants make the decision for them.
Here's the deal. HP apparently had this elegant old technology from Tandem that used specialized switches to map network IDs to hot-swappable compute modules. They re-introduced this technology as Virtual Connect for their blade servers because they figured it solved the problem of maintaining consistent network IDs when swapping out compute blades. In fact, Virtual Connect works pretty well - all you need to do is buy fault-tolerant pairs of specialized chassis-insertable switches to provide the ID mappings. That doesn't really force customers to change their network infrastructures, as some would suggest, but it does add a lot of cost to the blade solution.
Over the years Dell has been criticized for copying the technologies created by other companies. Brad Anderson, Dell's Senior VP of Business Products said as much last November after Dell announced its acquisition of EqualLogic:
“It’s fair historically, if you go back a year or so, that you would
have thought of Dell as more of a fast follower,” said Brad Anderson,
senior vice president of Dell’s business product group. “But we
recognize that if we want to solve our customers’ problems and provide
leadership, we’re going to need to jump in very early.” “With Michael coming back, things are a little bit different,”
Anderson, said. “Company-wide, we are driving IT simplification very
hard. It is our strategy; it is our mission. It’s also driving a
cultural change within Dell.”
In other words, when we see a good idea now, we don't just try to imitate it, but try to figure out how to make it as simple to use and efficient as possible. And that's what FlexAddress is all about. HP had done a pretty good job providing a solution, but it was originally designed for mainframe environments and not today's X86-based blade servers. As a result, Virtual Connect is over-engineered and expensive - there is no need for the specialized switches it uses.
Dell engineers figured out a much simpler way to provide persistent network IDs for blades as they are swapped or upgraded. The network IDs for each blade are mapped to another set of network IDs in the chassis according to slot the blade is inserted into. In other words, when a blade is removed and another blade is inserted in the same slot, it automatically is mapped to the same chassis-based network IDs - which means all LAN and SAN network functions work exactly the same as before. That includes VLANs and zoning and anything else you can think of. HP would have you think that all this has to be redone with FlexAddress, but it doesn't.
Maybe there are a few corner case advantages for Virtual Connect, such as lab environments where changes to blade configurations are more random and have less serious consequences. But in production environments where the rule of "if it ain't broke don't fix it" applies, the types of changes made to blade modules tends to be one to one replacements and upgrades. FlexAddress is perfect for this.
And one other thing. HP says that Virtual Connect was designed to enable the system admin to function independently of the network and SAN people. Oh really? And how are the proper tie-ins made from the Virtual Connect switching modules to the LAN and SAN switches anyway - by divination? C'mon guys - there is no free lunch.
So let's see now.... should I buy one SD card or a pair of expensive switches that cost approximately 10X as much? Hmmmm.....