In fairness, I used C-Mode at my last place and I can say a few things.
- the new cli isn't has hard to pick up as you might think. I feel within a 3 weeks or a month I was pretty comfortable with it. - there is a back way into the old ontap cli (it's not exactly the same, but close) for some debugging things. - the latency isn't nearly as bad as you might think. We had Nexus 5k's and many 10g links, and worked pretty smoothly. - While stability wasn't 100%, the failovers worked as expected and filesystems never stopped being served. This was 8.0 C-Mode - Moving data between cfo pairs is slick and awesome. Highly recommend 64bit aggrs.
All that said, I don't think a C-Mode cluster should be pushed unless 4 nodes are in it, two cfo pairs is what every c-mode cluster should start as. Two nodes doesn't make a heck of a lot of sense. I now live in a sea of Isilon and comparing and contrasting the two platforms is pretty interesting.
Hope that helps,
-Blake
On Tue, Jun 19, 2012 at 8:40 AM, Michael Bergman michael.bergman@ericsson.com wrote:
Darren Sykes wrote:
While I wouldn't disagree that it's a good product, having run GX, then 8.0C then 8.1C I'd argue that in a 2 node configuration C mode would be less reliable with little benefit over 7 mode at this point in time.
Quite... Functionality wise, C-Mode isn't finished yet either, there's quite some work for NTAP to do still. And it's not stable in the proper sense of the word -- 8.1 7-mode isn't stable yet either.
In fact, I'd probably wager that there will be a minimal performance degradation too.
There is. But it's not minimal, not in any sense of the word. With C-mode there's "local" and "remote" array access (the back-ends below the heads so to speak) and the additional latency induced by the cluster network is big. Really big. In use cases where you need to be down at 1 ms avg internal latency for NFS (with the help of PAM-II etc), for a fair NFSops load point, you can just forget about C-Mode yet. *Maybe* some time in the future, maybe it can be polished until 8.2Px or 8.2.1 is out... We'll see.
Less speed and reliability is a hard sell and that's before you even think about how difficult it'd be to move to C mode without buying more hardware.
Somehow "moving" to C-Mode without deploying a whole new system from scratch is unthinkable from there I stand. But of course it depends on the use case and other details.
I'd argue that at this point at least and for the next 24 months C-mode is pretty much like deploying a completely new (from a different vendor) storage system at your site in your environment, effectively potentiually doubling the complexity to handle for your storage ops ppl. Remember the CLI is completely different as well (for the large group of us who need/want to use that a lot, suppose a no of customers use the Web GUI way of controlling Filers to 100%)
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