On Wed, Jan 19, 2011 at 5:14 PM, Cory Coager <ccoager@xxxxxxxxx> wrote: > I would think even a low end DDR2 module would saturate the SATA interface > bandwidth. > > How would external journal to bcache help? Well, ram is more expensive per gigabyte than SSDs, particularly if you've got something with a battery attached - the idea would be to use your SSD for buffering 80 gb or so of writes, but then buffer all of bcache's metadata writes in battery backed-up ram, significantly decreasing the number of write IOPS to the SSD, and making it so pretty much all the writes to the SSD are big contiguous writes. > > On 01/19/2011 08:03 PM, Kent Overstreet wrote: >> >> Ahh, that makes sense. I'd be curious what performance you get - it >> certainly wasn't designed with ram in mind. You'll want to play around >> with the bucket size and see what works best, too. >> >> Also, in the future I'm going to add support for an external journal >> to bcache - that could be the best of both worlds, for you. > -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
