ORIGINALLY POSTED 7th May 2008
7,644 views on developerworks
Its been a while, and recently I’ve not had the time or inclination to comment about Hu’s blogketing, but a few of us found his recent post amusing. (As we often do)
I guess Hu has a dilemma. On the one hand he’s been telling us for a couple of years that Storage Virtualization in the array is the only way to do it, and you should buy USP, USP-V (or one of their clones). But now he has to make a case for the appliance too. I’ve always said that technically there shouldn’t be an real difference, when done correctly. Having some internal storage with your virtualization controller can solve some problems and provide an almost ‘stealth’ route to sell virtualization. Overall however he makes a great case for SVC… But two major points stood out in his post, and they both came in the same sentence!
When it comes time to replace the USP VM, you can continue to depreciate the storage system that you bought later by attaching it to the next generation USP V or VM.
One MAJOR thing missing here is that he doesn’t mention that replacing it will be disruptive. Just like it was migrating from USP or NSC-55 to USP-V or USP-VM.
Secondly, he tries to suggest you still need a big box too, you still need the USP-V – why? If the USP-VM could provide the performance needs of a true clustered appliance model, why would you want to buy a very expensive second layer of virtualization? Maybe its because the USP-VM has mediocre performance (but a low entry price) whereas USP-V has higher performance (and a much higher entry price). But you can’t upgrade from one to the other. Go figure. As per discussion comments on a recent post of mine, most SVC users see that all you need is a low cost, reliable, reasonably performing RAID brick.
Anyway, as I’ve covered many times before, there is no point having a great solution to solve your storage controller upgrade paths (online data migration etc) when you simply move the upgrade problem to the level above.
Again, as I’ve hopefully drummed into you, SVC can be upgraded without disruption from the smallest to the largest system and we can completely replace the SVC node hardware with the latest and greatest platform technology without disruption either.
So, remind me again, which provides for your virtualization needs and solves your upgrade woes?