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February 8th, 2012:

Soft Cache

VFCache is really yet more evidence that Storage Vendors are simply becoming software suppliers*; although ostensibly a hardware product; the smarts is down in the software layer and that is where the smarts are going to live. EMC are simply leveraging everything that they have learnt from PowerPath (Free PowerPath, Keep Fighting the Fight!) and using that to build on to introduce storage functionality on the server.

From the presentations we have seen so far, it seems that DeDupe is going to run on the server and not the card;  well, that’s my interpretation. Obviously this is going to have some interesting impact on CPU and memory utilisation meaning that EMC are going to have get this right or they risk the whole reason for putting cache closer to the server. Replication and cache consistency may also  be a server level function.

This does have some interesting implications; although it appears to be hardware product, how hard would it be for EMC to use any ‘flash’ technology which is installed in the server; do we have to have EMC hardware and could we use a Fusion-IO card or even a bog-standard SSD? What happens to the pricing?

EMC are already talking about accelerating any array; although it’ll be better with their own array but will they take this further and use anyone’s cache hardware? We’ll probably end up with another gargantuan certification matrix because EMC like those but it does seem possible. Perhaps Powerpath/Cache which allows a number of different vendor’s caching products to be used? This way EMC can monetise their software even further or perhaps, Powerpath/Cache comes free with VFCache but you need to pay to use it with third party cache products?

And what about file-based acceleration? Where do NAS and indeed Object storage fit into this? Do they? One of the biggest complaints or issues oft heard about object storage is that it can be slow, so would it benefit from some kind of caching; could cache hints be carried in the object metadata?

Also, it might be interesting to see how this could be integrated in the hypervisor stack? Perhaps a PowerPath/VE which support multiple vendor’s caching products?

Now EMC have validated PCIe local flash-cache concepts; we can start to move on and see where this takes us. And yes, someone other than EMC could have validated the concept but they didn’t; so let’s move on from there.

What are the other big vendors going to react with? IBM, HP, perhaps NetApp with SPAM (Server Performance Acceleration Module), HDS?

[* I’ve been thinking a lot about my recent experience with storage and whether storage teams may have more in common in with application teams than first thought; storage infrastructures tend to be more heterogeneous than other data centre infrastructures, certainly there is more vendor differentiation. ]