What are the pro's and con's of utilizing one Fibre adapter in a Fabric
environment to host both disk and tape? Should they remain separate in a Fabric environment? I get asked the question these days of, Can I place two Fibre Adapters in a system, have one for failover and/or redundancy, while having both disk and DLT tape (for backup) connected to both adapters? I understand that this would not be appropriate if one were FC-AL and the other Fabric due to LIP, but now that Fabric (the ability to log-on with a WWW) disk and libraries are available does this all become a reality? Thanks for your time and clearing this issue up for me!
In original FC-AL based SANs, tape and disk traffic had to be on separate adapters due to SCSI bus resets being generated by the tape subsystems, which affected disk based I/O.
In today's environments, using switches and Fibre to SCSI bridges, the tape traffic no longer affects disk traffic, due to a switched fabrics point to point nature. Connection to both tape and disk can now be provided over a single adapter, or dual adapters for performance/fail over capability. I would recommend using two adapters for availability, and perform backup over one adapter while production is up on the other. This would allow the data to stream more effectively to tape, while not impacting production.
This was first published in April 2001