Symmetrix and the death of monolithic arrays
V-Max is modular through and through
EMC's Symmetrix V-Max, announced today, represents the death of monolithic storage arrays and the rise of combined scale-up/scale-out modular arrays built from commodity components tied together with ASICs, very clever software and geographical distance cluster interconnects. It's also a tribute to 3PAR's T-Class InServ design and solidifies a trend to modularity seen already with the DMX-4.
The basic V-Max building block is a pair of quad-core Xeon 2.3GHx (5400) processors, 16 host and 16 disk enclosure ports (8 each per Xeon quad-core), 128GB of global memory, an EMC ASIC to handle the global memory access, and the RapidIO interconnect endpoints.
EMC can now ride the Intel CPU evolution curve and we can look forward to Nehalem-based V-Max engines, roughly twice as powerful as the existing ones at the quad-core level. (V-Max Plus anybody?) These should plug in and play with the existing 5400 Xeon-based ones providing both a scale-up upgrade path and investment protection.
We know that V-Max can scale to 8 V-Max engines with the current release and that FAST software is coming to provide automated data movement between the V-Max storage tiers (flash disk - Fibre Channel disk - SATA disk).
Barry Burke, EMC's senior director and chief strategy officer for the Symmetrix Product Group, says that EMC is developing software to leverage flash drives as something more than just another tier of storage, but doesn't explain what that means. Certainly, in the future, we might see 2-tier V-Max arrays; ones with just a fast flash tier and a bulk storage SATA tier.
V-Max memory considerations
The 8-engine V-Max has eight sets of storage enclosures behind the engines combined into a single logical pool of storage capacity, with the storage processors enjoying the use of global memory made up from each engine's own 128GB local memory, and presumably combined and kept coherent by the EMC ASICs. Any access to memory by a V-Max processor is treated as a local access, and remote accesses are virtualised to seem local.
As well as enabling two kinds of memory access, one local and the other remote to a peer V-Max engine, the architectural design allows for a third kind of memory access and linkage. Burke describes it: "the Architecture allows for a third dimension of interconnect – a connection between different V-Max systems. This interconnect would not necessarily expand to share memory across all the nodes in two (or more) separate V-Max arrays, but it would allow multiple V-Max arrays to perform high-speed data transfers and even redirected I/O requests between different Symmetrix V-Max 'virtual partitions.'"
"This capability of the Architecture will be leveraged in the future to 'federate' different generations of V-Max arrays in order to scale to even greater capacities and performance, and will also be used to simplify technology refreshes. In the future, you’ll be able to “federate” a new V-Max with the one on your floor and non-disruptively relocate workloads, data and host I/O ports."
It seems to me that V-Max virtual partitions could have different characteristics. Data in a partition might be single instanced and compressed Celerra-style, for example.
V-Max uses an interconnect new to most of us - RapidIO. Burke states: "the first generation of the Symmetrix V-Max uses two active-active, non-blocking, serial RapidIO v1.3-compliant private networks as the inter-node Virtual Matrix Interconnect, which supports up to 2.5GB/sec full-duplex data transfer per connection – each 'director' has 2, and thus each 'engine' has 4 connections in the first-gen V-Max."
Why was RapidIO used and not InfiniBand? After all, RapidIO has evolved from bus technology whereas InfiniBand is already used in processor clusters and storage clusters (Isilon). Sun has just chosen Mellanox' 40Gbit/s InfiniBand ConnectX adapters and InfiniScale IV switch silicon for its new line of Sun Blade modular systems and Sun Datacenter Switches.
The deal about SVC
> What's the deal about SVC?
Well, the deal is you can take a truckload of 'el cheapo' arrays, plug them almost braindead into a SAN and still get away with it since the SVC will provide all the management and redunancy to place enterprise workloads onto them.
Persistent rumor claims there are shops out there which have a pair of DS6k high performance/pricetag arrays and around two dozen of HP MSA2212/2312 (and a bunch of other stuff) arrays spread evenly across two datacenters quite some miles apart.
If you´d plug all those into an SVC cluster you´d be able to mirror drives without OS interaction, could evacuate arrays going down for maintenance and move demanding workloads temporarily (or permanent) onto the expensive storage without the clients ever noticing.
Well, the users call when their jobs suddenly run in 1/4th of their previous runtime. And then they call again when I move^H^H^H^Hwould move them back onto the MSA... ;)
Really unscrupolus Sysadmins woud even run Raid accross several cheap boxes and get amazing performance out of dirt-cheap arrays.
Even with the SVC licenses for far less than proper arrays would cost.
IBM SVC Tax
What's the deal about SVC?
V-Max is intelligent storage engines that communicate over a redundant fabric - Rapid IO. No intelligence in the fabric - Just really fast switches.
SVC is the hardware tax you pay to IBM to allow rebranded netapp, ibm, and whoever elses array IBM wants to sell this week to be managed as a single array.
Th idea of dropping in a new v-max array onto the floor and it federates itself into the virtual storage environment connected by a very high speed fabric is a very compelling vision of the future for data migration, business continuity, and disaster recovery.
looks like a DS8X00 on steroids...
´bout time someone copied IBM.
I mean, it´s not like the DS8k is exeptionally fast anyway ... But this whole Symmetrix thingie looks like a combination of a DS8k and a SVC.
 otoh, its also not exceptionally expensive, and I´d choose a good midrange array in my datacenter anytime above an enterprise arry in catalogue.