Good write up: Super scale out for flash
Posted: Wed Apr 22, 2015 3:38 pm
The Reg
Good stuffsScale-out flash arrays sound excessive but they are really not. After all, we can understand scale-out filers, adding node after node to store rapidly growing file populations.
Use cheap and deep disk for the data, with flash stashes used to hold the metadata and locate files fast. When the files are large then sequential access to and from disk is pretty fast as well.
But won't scale-out flash filers be monstrously expensive? Overkill, surely? Let’s have a look.
Scale out is less expensive than scale up. Instead of having a single, multiple controller head and complex backbone network fabric, as in monolithic DS8000/VSP/VMAX-style arrays, a scale out generally employs multiple independent nodes organised into a cluster which operates as a single system.
It means that when you get the array you don’t have to estimate how big it is going to become and buy all that capacity up front. For example, you might need 100TB now, and 120TB next year, 150TB the year after, 180TB after that and 200TB in year five – a total of 750TB.
Buy all that in year one and you have lots of capacity sitting idle. With scale out you can buy chunks of storage that are better tuned to how much you need when you need it.
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