Offtopic: VMWare IPO

13 08 2007

I’m going to digress from storage for a moment to discuss current events. In case you didn’t know, VMWare is going to become a public company tomorrow. I have been following this for several months as both an amateur investor and someone who deals with VMWare professionally, and I’ve been seeing lots of questions online about the IPO so figured I’d put together a quick post about some of the basics.

First, VMWare sells a software suite that allows multiple workloads to co-exist on the same Intel hardware. This is significant because Intel servers normally can not run more than one application at the same time, and Intel hardware is getting more powerful faster than applications can grow their basic requirements. Other platforms (like Unix and mainframe) were built from the ground up to do more than one thing at a time, but Intel cut its teeth in the desktop market, so did not inherit this quality. Now that Intel servers are powerful and reliable enough to trust many important company applications to, VMWare helps companies bring their average resource utilization from 10% up to 80% or higher by consolidating many light workloads onto the same physical machine.

VMWare is owned by EMC, a prominent storage solutions company. VMWare has been growing by leaps and bounds, and EMC wants to ensure that their investors can clearly see this jewel in their crown. Thus, they have decided to spin off about 10% of the VMWare stock publicly. Recently, Intel and Cisco both stepped up to the plate to buy a piece of VMWare before it went public.

EMC bought VMWare in 2004 for a steal, but had to agree to keep their noses out of VMWare’s business. This is relevant to VMWare’s bottom line because the biggest competitive differentiator they have with all the other virtualization solutions (like Xen and Microsoft) is that due to their two year head start, they have a massive list of solutions they’ve worked hard to ensure compatibility with (which includes some serious competitors to EMC). If your company uses a mainstream application and wants to run it under VMWare, chances are they’ve tested it and invested time and money into making sure it will work. Of course, they also have a head start in some of the niftier features like the ability to move around working applications from one server to another, but these features will eventually be canon for all virtualization while their partner ecosystem will still be years ahead of their competitors.

I think this addresses some common questions I’ve seen about VMWare and this IPO, but if anyone needs clarification, this is a Q&A blog, so ask away.

Advertisements




Storage and fabric virtualization

7 08 2007

Aloha Open Systems Storage Guy,

What’s your take on virtualization? VSAN from Cisco, SVC from IBM? What other virtualization products are available from other vendors?

Thanks,
John

Cisco VSANs and IBM’s SVC are different things for certain :)

The VSAN allows you to create multiple logical fabrics within the same switch- you tell it what ports are part of what SAN, and you can manage the fabrics individually. It’s especially useful if you’re bridging two locations’ fabrics together for replication or something because it allows you to do “inter VSAN routing” if you have the right enterprise software feature. That would allow you to have two separate fabrics whose devices can see each other, but if the link between the sites fails (which is more likely than a switch failure), you won’t have the management nightmare of having to rebuild the original fabric out of two separated fabrics when the link comes back. VSANs are also commonly used to isolate groups of devices for the purpose of keeping those devices logically separated from parts of the network they’ll never need to interact with.

IBM’s SVC is a different technology that is supposed to consolidate multiple islands of FC storage. It’s essentially a Linux server cluster that you place between your application servers and the storage. It allows you to take all the storage behind it and create what they call “virtual disks”- essentially a LUN that’s passed to a server but contains multiple raids (possibly from multiple controllers). This gives you the option of striping your data across more spindles than you would be able to normally, and allows you to do dynamic thin provisioning when your datasets grow.

The only downside of the Cisco VSAN technology I can think of is its cost- it’s bloody expensive compared to a cheap low end solution, and for anything less than a 50 device FC fabric, I would questionable whether it’s worth it. There is an alternative from Brocade/McData they call LSAN, however I am not as familiar with it. I have been told that it’s slightly less complicated, but harder to manage, and doesn’t have the full feature-set of Cisco.

The downside to the IBM SVC is that you create latency for all your disk reads- every time a server needs to perform a write, it has to go through the Linux cluster first. It has a much larger cache than most controllers, so there’s a better chance that the data you’re looking for is already there, but if it’s not, your read performance might suffer a little because of the extra few milliseconds. The advantage is that you can now use incredibly cheap controllers with tiny amounts of cache, and it allows you to migrate data from any manufacturer’s device to any other manufacturer’s device without interrupting your servers. Under a virtualized environment like this, an older DS4300 like you have will perform pretty much on the same level as a more expensive DS4800 or EMC CX3-80 (assuming the same number of drives) because you don’t really use the cache of the underlying system. Another advantage of the SVC is that most FC storage controllers charge you either one time or over time for the number of servers you’re planning to connect to them. IBM charges a “partition license” fee for LUN masking, and EMC charges a “multipath maintenance” tax. Either way, the multipath drivers for SVC are free, and it only needs one partition from the controller, so you might be able to save money that way.

Did you have any specific questions about these topics you want more detail on?

Also, one of the new bloggers in the storage world- Barry Whyte– focuses on IBM SVC. He just started, but his blog will hopefully become a real resource for people with IBM storage virtualization on their mind.