Please note that IO speeds exceeding 1 GB/sec  can be limited by several
components including the OS or device drivers. 
Currrent maximum performance I have seen is around 1,25 GB through dual IB.
Anyway, that's a great realworld performance, considering the price and size
of the unit. 



Mertol Ozyoney 
Storage Practice - Sales Manager

Sun Microsystems, TR
Istanbul TR
Phone +902123352200
Mobile +905339310752
Fax +902123352222
Email [EMAIL PROTECTED]



-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Lida Horn
Sent: Wednesday, June 25, 2008 11:14 PM
To: Tim
Cc: zfs-discuss@opensolaris.org
Subject: Re: [zfs-discuss] raid card vs zfs

Tim wrote:
>
>
> On Wed, Jun 25, 2008 at 10:44 AM, Bob Friesenhahn 
> <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> 
> wrote:
>
>     I see that the configuration tested in this X4500 writeup only uses
>     the four built-in gigabit ethernet interfaces.  This places a natural
>     limit on the amount of data which can stream from the system.  For
>     local host access, I am achieving this level of read performance using
>     one StorageTek 2540 (6 mirror pairs) and a single reading process.
>     The X4500 with 48 drives should be capable of far more.
>
>     The X4500 has two expansion bus slows but they are only 64-bit 133MHz
>     PCI-X so it seems that the ability to add bandwidth via more
>     interfaces is limited.  A logical improvement to the design is to
>     offer PCI-E slots which can support 10Gbit ethernet, Infiniband, or
>     Fiber Channel cards so that more of the internal disk bandwidth is
>     available to "power user" type clients.
>
>     Bob
>     ======================================
>     Bob Friesenhahn
>     [EMAIL PROTECTED]
>     <mailto:[EMAIL PROTECTED]>,
>     http://www.simplesystems.org/users/bfriesen/
>     GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
>
>     _______________________________________________
>     zfs-discuss mailing list
>     zfs-discuss@opensolaris.org <mailto:zfs-discuss@opensolaris.org>
>     http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>
>
>
> Uhhh... 64bit/133mhz is 17Gbit/sec.  I *HIGHLY* doubt that bus will be 
> a limit.  Without some serious offloading, you aren't pushing that 
> amount of bandwidth out the card.  Most systems I've seen top out 
> around 6bit/sec with current drivers.
Ummm 133MHz is just slightly above 1/8 GHz.  64bits is 8 x 8 bits.  
Multiplying yields 8Gbits/sec or 1GByte/sec.
So even if you have two PCI-X (64-bit/133MHz slots) that are 
independent, that would yield at best 2GB/sec.
The SunFire x4500 is capable of doing > 3GB/sec I/O to the disks, so you 
would still be network
band limited.  Of course if you are using ZFS and/or mirroring that 
 >3GB/sec from the disks goes
down dramatically, so for practical purposes the 2GB/sec limit may well 
be enough.
>
>
> ------------------------------------------------------------------------
>
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> zfs-discuss@opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>   

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