It's not an official pronouncement, but the Using IBM LTO Ultrium with Open
Systems redbook SG24-6502 has this statement on page 24:
Restriction: At this time, sharing a HBA with Disk and Tape is NOT
recommended. In many instances, the microcode or device drivers HBAs
required to support the different devices makes this impossible in any
case. In
addition, disk and tape usually generate very different types of I/O
accesses,
and using the same HBA will likely give poor performance. You should check
with your local support organization for details of specific recommended
and
supported combinations.



_____________________________
William Mansfield
Senior Consultant
Solution Technology, Inc
630 718 4238


                                                                                
                                                       
                      Allen Barth                                               
                                                       
                      <allen_barth@SCUD        To:       ADSM-L AT VM.MARIST 
DOT EDU                                                          
                      DER.COM>                 cc:                              
                                                       
                      Sent by: "ADSM:          Subject:  Re: Bad performance 
with FC attached disk and tape                            
                      Dist Stor                                                 
                                                       
                      Manager"                                                  
                                                       
                      <[email protected]                                         
                                                       
                      .EDU>                                                     
                                                       
                                                                                
                                                       
                                                                                
                                                       
                      02/21/2002 03:58                                          
                                                       
                      PM                                                        
                                                       
                      Please respond to                                         
                                                       
                      "ADSM: Dist Stor                                          
                                                       
                      Manager"                                                  
                                                       
                                                                                
                                                       
                                                                                
                                                       




Joshua,

I've heard this before, but I couldn't find anyone at IBM to confirm it.
SO.........

I've been running tape and dasd thru the same FC adapter for about a year
now.  Traffic goes from rs6k to an IBM2109 (brocade) switch and then splits
from there.  I suspect the switch is handling the arbirated loop (3590) and
point to point (ess aka shark) communication conversions.

Gotchas?

Al Barth
Zurich Scudder Investments





                    "Joshua S.

                    Bassi"               To:     ADSM-L AT VM.MARIST DOT EDU

                    <[email protected]       cc:

                    OM>                  Subject:     Re: Bad performance
with FC attached disk and tape
                    Sent by:

                    "ADSM: Dist

                    Stor Manager"

                    <ADSM-L AT VM DOT MAR

                    IST.EDU>



                    02/21/02 12:56

                    PM

                    Please respond

                    to "ADSM: Dist

                    Stor Manager"







Not only is sending disk and tape data across the same FC card a bad
idea, I believe IBM doesn't even support that configuration.



--
Joshua S. Bassi
Joshua S. Bassi
Sr. Solutions Architect @ rs-unix.com
IBM Certified - AIX/HACMP, SAN, Shark
Tivoli Certified Consultant- ADSM/TSM
Cell (415) 215-0326