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4x FC from Media server to brocade 300 to i6000 tape robot.

Level 4

I have a Media server with 4x8GB FC connections. I am trying to get as much B/W to the robot as I can.

I'm not concerned with failover of SAN paths, I purely want 4x8GB of B/W to make sure I'm not starving the robot.

Can Netbackup do this? Is there a special license I need for this?

In terms of the San would I make 36 zones and configure 1:1 in each zone (4 cdonnections on the media server to 9 tape drives so 36). Within netbackup would it see these and realize, it's got 4x paths to the 9 drives or does extra config inside netbackup need to take place. Would this involve linux multipathing?

Here are my WWNs


I'm really lost atm.


Level 4

I've been using FC tape drives for a number of years and in my experience multi-pathing to them is not a spectacular experience.

In your scenario, NBU would detect 9 drives and 4 paths for each drive, but it would only use 1 path at a time.  And from what I recall, there isn't any mechanism to rotate or load balance the port usage.

The last time I had multi-pathing to my drives, we decided that the configuration wasn't healthy for us and reduced each drive down to 1 path.

You could split them up, 2 on each path (and one path with 3) though?

EDIT: Just saw you're using Linux (should have lead with that).  My media severs were Windows, so Your Mileage May Vary differently under Linux.  But from the NBU side of things, I don't believe there is multi-path rotation/balancing for devices like you're thinking.

So for example having 9 drives, how would yuou even get decent b/w to them then with a 1:9 setup (1 server WWN, 9 remote LTO WWNs).


Or would be purchase more media servers and keep the 1:9 ratio. That just seems insanely more expensive/complicated.


I'm trying to figure out how best to get this working properly.

Counting the devices in proportion to the server isn't really how I would think of it.

Depending on the specs of the server, it would be plenty adequate to run all your drives.

The better way to think of the proption is the bandwidth of the devices connected to each HBA port.

So, your HBA ports are 8Gb and you connect 2xL7 drives (8Gb each), so you have a 2:1 ratio on that port.


I would put 2 drives on each port (and 1 port has 3) unlress your media server is low on cpu/ram, it should handle that fine.  If it is low/modest, then maybe you go with 2 media servers and do 1 drive per HBA port.

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Or put more FC HBA ports in the media server.  One site I worked at once had four Sun (Oracle) M5000 Solaris based media servers each with seven dual port HBA (yes that is fourteen 8Gb initiator ports in each media server) roughly a third of which were for reading disk array targets (VM storage), and two thirds for writing to tape drive targets - but you'll have to do your own sizing and modelling of traffic profiles of VM LUN read traffic versus LAN client traffic.

Tape multi-pathing is generally not possible.

As others have suggested the best config is likely to be something along the lines of 1:2 (i.e. one initiator two targets) - but this is totally dependent upon port speed and tape drive capability - but even then you need to remember that there's no point having a lovely balanced tape writing egress setup if the VM disk reading and/or client LAN traffic ingress is poor / rubbish.