Re: Fiber channel: Continue to virtualize through vios or not?

Le 28/01/2022 à 15:19, Rob Berendt a écrit :

We are using fiber channel for connecting our VTL only. No SAN used by our Power systems at this time. We virtualize disk from a hosting lpar of IBM i to other lpars of IBM i and AIX.
Right now we have it virtualized via VIOS to our lpars of IBM i.
We're at IBM i 7.4 with reasonably recent PTF's.
We have two lpars of vios on each power system. Vios is used to virtualize Ethernet and Fiber Channel. We've got redundancy on the Ethernet to where an lpar of vios could go down and we should run fine. Seems to work ok during testing, like some vios upgrades midweek.
We never set up redundancy for the fiber channel. Right now we have the physical cables in there but never got around to virtualizing them from more than one vios lpar. I guess we figured it wasn't necessary or worth the effort back then. Now we're second guessing that. Not so much for redundancy but more for load. When we are running backups on multiple lpars at the same time the switch is showing the 8gb fc is getting a lot of exercise.
We're upgrading our VTLs from DD2500's to 6900's (please no sales calls, the new units are already in storage). This would be a good time for a change.
How do you do this kind of load balancing?
Do we need to still use VIOS? If not "needed" does it still provide an advantage?

Hello

I am not familiar with IBM i hosting IBM i but, talking about IO virtualization including redundancy, the main functions can be provided by both VIOS and IBM i host. However, virtualization optimization is probably higher on VIOS. Capabilities like NPIV, Ethernet automatic failover are not here on IBM i hosting (AFAIK) (though automatic failover can be achieved with VIPA).

IMO, the main advantage of VIOS is about providing advanced features such as Live Partition Migration and Simplified Remote Restart. But, it requires a minimum of AIX knowledge, even if IBM did some effort to simplify the setup and configuration process. So, if you have this skill in your company, VIOS will probably be more efficient. If you want to apply LPM and SRR, there is no option but VIOS. If you do not have AIX skill and do not plan to use advanced functions, the discussion is open (on my side I remain a VIOS pro, just because it is built for IO virtualization).

Regarding tape redundancy, you achieve it with tape multipath. Checkout https://www.ibm.com/support/pages/ibm-i-removable-media-tape-multipath and https://www.ibm.com/support/pages/ibm-i-removable-media-tape-library-virtualization. I do not know anything about DD VTL so I do not know if they support IBM i multipath but I would be surprised if they do not. In the IBM documents above, the connection from the IBM i partition to the tape drives does not matter for enabling multipath. As soon as there are, at least, two distinct paths, you can enable it. With a VIOS and NPIV, it is only a matter of configuring a pair of client/server virtual fibre channels adapters, mapping virtual adapters to physical adapters within the VIOS, setting up the zoning with tape drives WWNs. Then, as for any connection method, work is needed on the VTL. I am not aware of any automatic way to balance the tape workload, but it can be manually set through the mapping in the VIOS and with the preferred path in the IBM i partition.

My 2 cents