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One major advantage of a mainframe vs commodity built clusters with similar capacity is internal bandwidth. With clusters, you are limited by your network speed
by astine 16y ago
One major advantage of a mainframe vs commodity built clusters with similar capacity is internal bandwidth. With clusters, you are limited by your network speed. A high end ethernet based network is about 10Gbit, and you can reach higher with specialty hardware like Infiniband, but then you're no longer using commodity components. Within a mainframe your interprocess bandwidth is limited only by your bus speed. Problems that things like memcached are meant to solve are no longer a concern.
- rbranson 16y agoHow is Infiniband not commodity? It's not GbE cheap, but it's also a lot lower latency and 20x-40x the bandwidth. Infiniband is about $250-$500 per port, which is around what 10GbE costs right now.
- mmt 16y agoI had been dismisising Infiniband out of hand for a few years now, assuming it remained too uncompetitively[1] expensive, much as 10GE has. However, 2-4x the bandwidth (and lower latency) than 10GE, for the same price, could make it compelling. Does the price you quote include all of host adapters, cables, and switch ports? How is Infiniband not commodity? How many suppliers are there for the critical components? There may be more than one vendor for adapters, but if they all use the same HBA-on-a-chip, the market hasn't yet been commoditized. [1] Since my POV is centered around disk I/O, it would compete against SAS. Per 8-lane bundle, it's 24x the bandwidth at about $400 at the host and $100 at the expander, as of the previous generation. The current generation doubles the bandwidth, though I don't have reliable "street" prices yet.
- wmf 16y agoWithin a mainframe your interprocess bandwidth is limited only by your bus speed. You're ignoring System p, Superdome, Altix, Beckton, etc. which are also big SMPs but are significantly cheaper and easier to use than mainframes.