MAD Blog: The E in EMC Stands For Emulated
Yes, it does, I tell you. EMC is not what you think it is; it's emulated! The real EMC wants to hide this from you!
Only kidding. With EMC, what you see is what you get. Unfortunately.
Point in case; here's EMC's uber blogger, Chuck Hollis, on the subject of EMC's FC solutions over NetApp's, specifically about the NX4;
Like other Celerras, it does the full unified storage thing: iSCSI, NAS and "real deal" FC that isn't emulated.
The FC is native, and is not mediated by the NAS head.
In his comments, Tony Asaro can't quite fathom this out. He wasn't alone. Chuck bounces back, and over a series of comments (my bold italics);
But you lose the thread there -- most FC care about predictable performance behavior, and emulation can often get in the way of that, as you lose the underlying geometry and device characteristics.
Regarding disk geometry, NetApp (as do all emulated environments) attempts to emulate physical disks using a file system.
The real debate is --- when you need FC and what it does well, are you better off with an emulated version, or a native implementation?
My point is that -- at the application level -- emulated FC drives behave differently than real ones. And, in many cases, it can matter.
There's a mishmash of ideas here. FC stands for everything; drives, protocols, storage heads, even disk geometry is relevant. But the L for Logical in LUN seems to have somehow passed by without a mention. Clever, clever NX4!
Sigh. Still, we did get one admission.
I have no basis to comment on NetApp's specific implementation of the FC protocol. Unless I talk to one of our FC engineers, I just wouldn't know. Or know if any deficiencies or advantages really mattered.
That would have been a good move before blogging on the subject, no?.
So go and ask an engineer to explain what "emulated FC" is. Then come back and let me know. Personally, I'm betting on "Uhmmm...", and a puzzled look.
I'm grateful to Kostadis for the MAD blog idea. if you're tired of reading posts where vendors try and poke each other in the eye, just skip the ones marked MAD.
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