Chris Worley wrote:
On Tue, Nov 10, 2009 at 8:48 AM, Asdo <asdo@xxxxxxxxxxxxx> wrote:
I have not heard about these SSS you mention.
Do you have a link?
All the Fusion-io products (fusionio.com) and TMS's (ramsan.com) RS20
are two examples (not their RAM-based products). Sun has their
"Sunfire", but I haven't seen that yet.
I don't know TMS, I know Fusion-io a bit: it is indeed 10x faster than a
SSD but it is also 10 times more expensive!
If you make a raid-0 of ten SSDs in a good hardware-raid controller,
exported to the OS as a single SCSI disk, I bet you obtain about the
same performances.
Look at this:
http://www.tomshardware.com/reviews/x25-e-ssd-performance,2365.html
by looking at this page
http://www.tomshardware.com/reviews/x25-e-ssd-performance,2365-7.html
it seems the "streaming writes" is apparently similar to the benchmark
you want (see the specs), do you agree? Yes it's 0% random it's 4
workers... and the blocksize is the one you want.
You find the result in the following page. That's 2.2GB/sec with 16
disks. If you imagine it with 8 disks and only 1 controller (the
benchmark uses 2 controllers with a software raid-0 above) it's more
than the speed you want (800MB/sec) and it's with a SCSI interface.
What do you think?
Also are you sure that the SATA/SCSI layer is the problem? Some hardware
raids can do 800 MB/s sequential, single stream, and indeed with a SATA/SAS
interface to the kernel. If what you say was true, that would be
impossible...
Sequential/streaming performance is a corner case. There are many
high speed solutions to that (even using rotating media). I'm talking
random I/O at 128KB blocks at 800MB/s per drive.
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