From mboxrd@z Thu Jan 1 00:00:00 1970 From: Default User Subject: Re: Intel Updates SSDs, Supports TRIM, Faster Writes Date: Wed, 11 Nov 2009 19:02:37 +0100 Message-ID: <4AFAFC3D.3000402@email.it> References: <4AF7066C.1040507@tmr.com> <70ed7c3e0911081713m7184356buadd6b102fe4755e8@mail.gmail.com> <70ed7c3e0911090842i167175a0q44fc5ad50a2f1759@mail.gmail.com> <1257846132.22155.155.camel@localhost> <4AF98B4C.6080805@shiftmail.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: Sender: linux-raid-owner@vger.kernel.org To: Chris Worley Cc: linux-raid List-Id: linux-raid.ids Chris Worley wrote: > On Tue, Nov 10, 2009 at 8:48 AM, Asdo 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. >