Re: Intel Updates SSDs, Supports TRIM, Faster Writes

[Default User <default_user@email.it>]

Chris Worley wrote:
> On Tue, Nov 10, 2009 at 8:48 AM, Asdo <asdo@shiftmail.org> 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.
>