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On May 22, 2008, at 19:54, Richard Elling wrote:
> The Adaptive Replacement Cache
> (ARC) uses main memory as a read cache. But sometimes
> people want high performance, but don't want to spend money
> on main memory. So, the Level-2 ARC can be placed on a
> block device, such as a fast [solid state] disk which may even
> be volatile.
The remote-disk cache makes perfect sense. I'm curious if there are
measurable benefits for caching local disks as well? NAND-flash SSD
drives have good 'seek' and slow transfer, IIRC, but that might
still be useful for lots of small reads where seek is everything.
I'm not quite understanding the argument for a being read-only so it
can be used on volatile SDRAM-based SSD's, though. Those tend to be
much, much more expensive than main memory, right? So, why would
anybody buy one for cache - is it so they can front a really massive
pool of disks that would exhaust market-available maximum main memory
sizes?
-Bill
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