On Sep 10, 2008, at 11:40 AM, Bob Friesenhahn wrote: > > Write performance to SSDs is not all it is cracked up to be. Buried > in the AnandTech writeup, there is mention that while 4K can be > written at once, 512KB needs to be erased at once. This means that > write performance to an empty device will seem initially pretty good, > but then it will start to suffer as 512KB regions need to be erased to > make space for more writes.
That assumes that one doesn't code up the system to batch up erases prior to writes. ... > returns to the user faster. This may increase the chance of data loss > due to power failure. Presumably anyone deft enough to design such an enterprise grade device will be able to provide enough super-capacitor (or equivalent) to ensure that DRAM is flushed to SSD before anything bad happens. Clever use of such devices in L2ARC and slog ZFS configurations (or moral equivalents in other environments) is pretty much the only affordable way (vs. huge numbers of spindles) to bridge the gap between rotating rust and massively parallel CPUs. One imagines that Intel will go back to fabbing their own at some point; that is closer to their usual business model than OEMing other people's parts ;> -- Keith H. Bierman [EMAIL PROTECTED] | AIM kbiermank 5430 Nassau Circle East | Cherry Hills Village, CO 80113 | 303-997-2749 <speaking for myself*> Copyright 2008 _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
