On Thu, Jan 06, 2011 at 02:19:04AM +0100, Spelic wrote: > >CPU can handle considerably more than 250 block hashings per > >second. You could argue that this changes in cases of sequential > >I/O on big files, but a 1.86GHz GHz Core2 can churn through > >111MB/s of SHA256, which even SSDs will struggle to keep up with. > > A normal 1TB disk with platters can do 130MB/sec sequential, no problems. > A SSD can do more like 200MB/sec write 280MB/sec read sequential or > random and is actually limited only by the SATA 3.0gbit/sec but soon > enough they will have SATA/SAS 6.0gbit/sec. By âsoon enoughâ you really meant âa year agoâ, I think: http://www.anandtech.com/show/3812/the-ssd-diaries-crucials-realssd-c300 Current 6Gbps SSD are doing 415 MB/s sequential: http://www.anandtech.com/show/4086/microns-realssd-c400-uses-25nm-nand-at-161gb-offers-415mbs-reads or even claim 550MB/s: http://www.anandtech.com/show/4100/ocz-vertex-pro-3-demo-worlds-first-sandforce-sf2000 (funny bit: Sandforce SSD controllers dedup internally). Anyway, 6Gbps is not a future tale, but something long available. And not the fastest kids on the block: currently build filesystems must deal storage providing many gigabytes per second. Think of massive disk arrays or stuff like Oracle F5100, claiming 12.8GB/sec read and ~10GB/s write (in one rack unit). -- Tomasz Torcz "God, root, what's the difference?" xmpp: zdzichubg@xxxxxxxxx "God is more forgiving." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
