RE: iFCP as an IP Storage Work Item

["Y P Cheng" <ycheng@advansys.com>]

> As I see it, the software issue is not only related to support for the
> low-level hardware and SCSI encapsulation.  It's in the effort needed to
> transpose all the SAN value-add (naming, discovery, zoning, error
> recovery, management, etc) to a new network environment.
> ......... <snip> <snip> .............
> So, rather than say that the iFCP preserves the existing driver stacks, we
> should go further and extend the scope to the totality of
> software needed to support the storage network environment.
>
> Charles

Yes, we are now talking the right area.  However, I don't see how iFCP will
help preserve the software and hardware investment of SAN environment made
by customers.  Here is my understanding of the investment made by customers
in SAN environment.  (Experts of SAN can certainly correct me.)

1. Software from Oracle, Veritas, and Logato running in block address
instead of file system address.  I am pretty sure none of those software is
specifically programmed for FCP devices.  In fact, they treat everything
like "hard disks or tapes" whether they are ATA, SCSI, FCP, or RAID. Shark
and Symmetrix mentioned by you appear to the application software as
reliable hard disk devices.

2. SAN management and configuration software.  These are typically provided
by storage device manufacturers.  The software talks to the storage devices
through a separate Ethernet connection.  Most storage boxes use SNMP to send
and get Management Information Blocks (MIBs).  Again, iFCP is not
particularly helpful in saving the investment in this area.

3. Hardware investment like routers and switches.  The Name Server inside
the switches provides target device discovery function.  With Java support,
the switches provide customers the comfort at home using a browser to log
into the switches to check connectivity and do zone and domain management.
In such case, FCIP is in a better candidate to preserve the existing
investment.

4. Finally, the HBA's inside the servers and storage devices.  I can assure
you, every HBA manufacturer will have device driver to do FCP, iSCSI, iFCP,
or FCIP stack processing, whatever protocol chosen by the customers.  The
protocol stack processing are done inside the IC by microcode, not the
device driver.  Even MicroSoft Winsock Direct and TCP Remote DMA will be
implemented in the microcode of the IC to offload the host protocol stack
processing. No software investment is made by customers.  (The drivers are
free with the HBA.)

In all, if I may summarize, the strongest argument iFCP has is the OSPF
routing and scalability.  But, FCIP gets OSPF routing in the IP plane too.
For the scalability, storage-device attachment to servers is somewhat static
and confined, unlike the HTTP which requires huge amount of connectivity and
IPv6.  No Internet or dot com companies would need 16 million block-device
addresses allowed by the 24-bit D_ID of FCIP at one time.  :-)

Y.P. Cheng, ConnectCom Solutions.