[CentOS] Re: Gfs and storage -- [OT] FC-AL, iSCSI, AoE and SAS ...

Fri Aug 26 17:12:40 UTC 2005
Bryan J. Smith <b.j.smith at ieee.org>

Jay Leafey <jay.leafey at mindless.com> wrote:
> As an aside, has anyone looked at using GFS with the
> ATA-Over-Ethernet stuff from Coraid?  It appears to
> have the potential for better performance than iSCSI
> (no walking up and down the IP stack).

I looked at their design and it doesn't seem to address the
multi-targeting aspects very well.  In other words, I see a
lot of complications for clustering because they have not
addressed them, which is left to GFS to address.  I think I'd
rather use another storage solution that either handles
multi-targetting better, or is just much faster for close to
the same distance limitations.

Serial Attached SCSI (SAS) is the next generation of
multi-targettable SCSI.  It is far higher performing and very
competitive with FC-AL on speed, but at a massively reduced
price-point and even less overhead.  The only disadvantage is
length, limited to 8m (~26'), although it can be repeated
just as far as AoE.  So it's ideal for clustering in the same
closet/room, or repeated to nearby areas.

I personally see AoE getting crushed between multi-vendor
FC-AL/iSCSI lengths and SAS performance.  Especially given
that SAS already uses the proven SCSI-2 protocol and stack,
whereas AoE is one vendor right now.  I know a lot of people
are talking about AoE because they've done the "conference
circuit," but once people hear about SAS, they quickly
reconsider.

For more on SAS, see my blog:  
http://thebs413.blogspot.com/2005/08/serial-storage-is-future.html
 


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