FC Switch Configuration for Tape Library to NetBackup Device

[tcoed]

Hello all! I am new to the world of working with backup appliances. I have an IBM TS3200 tape library with 4 FCs, and a NetBackup appliance with only 2 FCs. I cannot find anything on multiple vendor sites about configuring the intermediary Cisco FC Switch to make this work. For instance, I don't know what kind of switch I need to use, can I use a simple 3750 or 3850 and put everything on the same VLAN, or do I need a special SAN switch? I need for the NetBackup to be able to see all four drives on the tape library. If anyone has links I can use, I'd be very grateful. So far the vendor sites of Cisco, IBM, and Symantec don't have anything that I can find so far for network admins like myself. Thanks!

[sdo]

First some questions.

1) How many tape drives?

2) Two dual ported tape drives, or four single ported tape drives?

3) How many FC switches do you have?

4) Do you have one FC SAN switch with at least 6 free unused but licensed ports?

5) Or, do you have two FC SAN switches each with at least 3 free unused but licensed SAN switch ports?

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If you have two tape drives, and they are dual ported - then you do NOT need a SAN switch to get this working.  Instead, you could forgoe tape multi-pathing, and instead simply cable directly between one port of the appliance, and one port of each tape drive - and therefore no need for SAN switch or SAN zoning.

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If you have four tape drives and you want to get going quickly, then simply do not cable two of the tape drives, and instead at least get two of the drives working whilst you think about possibly acquiring a SAN switch.  NetBackup will 'see' the other two unused tape drives when it talks to the tape library, but will simply ignore them, no problems.

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If you have four single ported tape drives, and you want to use all four tape drives, then you have two choices:

1) will need either a SAN switch to implement a SAN fabric.

2) or you will need an additional dual port FC HBA in your appliance to cable directly between four appliance ports and four tape drive ports.

.

If you want to go the FC SAN switch route, then you will need:

- at least one FC switch to use FC tape with FC HBAs

- with enough free, unused, but licensed ports

- with FC SFPs already in each port to beused

- of the correct type (probably SW (short-wave)), and correct speed (probaby 8Gb), and correct specifications (FC SAN and *not* LAN) and correct laser frequency.

- and of course the correct fibre cables of the correct specification (there are several/many different cable types - and you will need to get 'exactly' the right type), with the correct 'plug' ends to match (i.e. there are at least three different plug-ends on thr market, and you need to get cables with teh correct plugs/ends):

     1) FC sockets on the tape drives          to        FC sockets of the SFP in the SAN switch

     2) FC sockets on the appliance HBA    to        FC sockets of the SFP in the SAN switch

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If you don't have a FC SAN switch with licensed free ports, then we're not going to get very far.

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If you want to go the FC SAN switch route, then I may be able to help you with your SAN FC zoning configuration too - once you get it licensed and with the correct SFPs installed.

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Some basics:

B1) To talk to FC tape drives, you need FC connectivity.

B2) FC "inititator" typically the source (i.e. the HBA within the appliance) which, when a SAN switched fabric is present will perform an FLOGI and PLOGI to logon to the SAN fabric.

B3) FC "target" typically the storage device (i.e. the FC port(s) on the tape drives) - or front end ports of a disk array.

B4) All SAN FC ports (of initiators and targets) will have a WWPN - which you can loosely think of as being a bit like a MAC address.

B5) When zoning on a SAN fabric, an admin will configure a "zone" between WWPN's (and not between WWN's or WWNN's).  Google if you want to know more.

B6) Final top tip:   Single initiator zoning is best practive.  But we can cover more of that later if you want.

[sdo]

If you go the single SAN switch route, then be careful, some of the cheaper SAN switches have only one power supply - and thus represent a single point of failure for your backup solution, not good - so, because these cheaper SAN switches only have one power supply, they are meant to be used in pairs, i.e. 'two at a time' - to create either:

a) a single fabric of two switches  (but then if you corrupt your 'fabric config' then you've lost your SAN, not good).

b) dual fabrics each of one switch  (safer, because there are two SAN fabric 'configurations', each with their own private 'fabric config') (only slightly harder to administer) (but more complex to think about).

[tcoed]

Thank you for the information. I will take this and do some digging, then come back for more after I have exhausted my KB. I really appreciate you taking the time to write this all out, and it looks like Google and I will be busy tonight. I don't want to waste any more of your time until I have attempted to educate myself first! What I am gleaning from this is:\ 1. I will need a SAN FC switch to do this, not just a regular FC switch. 2. With a SAN switch, I'll be able to configure it such that my four "target" FC ports on the tape library will be recognized by the Symantec 5200 NetBackup Appliance, even though it will be connecting through the 2 available "initiator" FC ports. Google and I will be educating ourselves on zoning and SAN fabrics tonight. Thanks again for your advice, and i may be hitting y'all up tomorrow for more. I really do appreciate it!

[tcoed]

BTW, if any of you could recommend a good book that might be able to educate me on everything I need to know as a Network Admin, that would be really helpful. I'd prefer not to bother anyone else if I can learn this on my own.

[sdo]

I am most definitely not being facetious with this, I've read it, and this really is a great beginners book, and a very quick read, and very cheap here too for a print version:

http://www.abebooks.co.uk/servlet/SearchResults?sts=t&tn=storage+area+networks+for+dummies

...but I bet you can get latest revision on Kindle, and maybe even in Apple iBook store.

[sdo · Accepted solution]

The Cisco 3750 or 3850 are LAN switches, and as far as I know cannot do SAN FC.

SANs don't have VLANs.  SANs can have VSANs, and you'll have to read up on that - but I doubt very much you will need VSANs - as these are typically used in much larger installatons.

Most Brocade SAN switches have zero port contention, i.e. all SAN switch ports can Tx/Rx at full speed at all times with zero bandwidth contention.  AFAIK, many Cisco SAN switches have port group contention.

Most Broacde SAN switches have feature called 'cut through routing' which can be just great for storage as it completely and utterly eradicates any concept of packet latency.  AFAIK, no Cisco SAN switches have this feature.

Need a link for cut-through routing?

My recommendation is a Brocade SAN switch.  Not cheap, but you get what you pay for.

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I think what you might be "missing" is just how easy SAN "zoning" really is, once you get your head around it.

Collect the FC HBA WWPNs from the appliance.  These are your initiator WWPNs.

Collect the FC Tape Drive WWPNs from the tape library.  These are you target WWPNs.

Here's an example for Brocade to zone the two appliance FC HBA ports to four FC tape drives:

$ alicreate AL_APPLIANCE1_HBA1_PORT1, "nn:nn:nn:nn:nn:nn:nn:nn"

$ alicreate AL_APPLIANCE1_HBA1_PORT2, "nn:nn:nn:nn:nn:nn:nn:nn"

$ alicreate AL_TS3200_TAPE1, "nn:nn:nn:nn:nn:nn:nn:nn"

$ alicreate AL_TS3200_TAPE2, "nn:nn:nn:nn:nn:nn:nn:nn"

$ alicreate AL_TS3200_TAPE3, "nn:nn:nn:nn:nn:nn:nn:nn"

$ alicreate AL_TS3200_TAPE4, "nn:nn:nn:nn:nn:nn:nn:nn"

$ zonecreate ZN_APPLIANCE1_HBA1_PORT1, "AL_APPLIANCE1_HBA1_PORT1; AL_TS3200_TAPE1; AL_TS3200_TAPE2"

$ zonecreate ZN_APPLIANCE1_HBA1_PORT2, "AL_APPLIANCE1_HBA1_PORT2; AL_TS3200_TAPE3; AL_TS3200_TAPE4"

$ cfgadd CFG_FAB_A, "ZN_APPLIANCE1_HBA1_PORT1; ZN_APPLIANCE1_HBA1_PORT2"

$ date

$ cfgsave

$ date

$ cfgenable CFG_FAB_A

$ date

$ exit

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The above assumes you have a 'config' named 'CFG_FAB_A' that already exists.  If it's a new bare bones SAN switch and no pre-existing config, use the 'cfgcreate' command instead of 'cfgadd'.

(BTW - there are other things that you should do first when configuring a new SAN switch - so you'll have to read the guides on that).

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With the above, you will have created two zones, each with a single initiator, and each with two targets (tape drives).

After this, on the appliance, re-set the HBAs.

Then on the tape library management GUI - present the robot control and tape drives as LUNs to the required WWPN "initiators" (which should auto-popup in the tape library management GUI).

Back on the appliance scan for tape.

Run the device configuration wizard in the NetBackup GUI.

And you should be good to start using the NetBackup 'storage unit' for the tape library (and NetBackup will know that the storage unit has four tape drives).

HTH.

[sdo]

1. I will need a SAN FC switch to do this, not just a regular FC switch.

A: To be honest, I'm not aware of the distinction.  This is new to me.  I always thought an FC switch was a SAN switch.  Could you share with me the distinction?

2. With a SAN switch, I'll be able to configure it such that my four "target" FC ports on the tape library will be recognized by the Symantec 5200 NetBackup Appliance, even though it will be connecting through the 2 available "initiator" FC ports.

A: Yes.  Zoning two tape drive targets ports to one appliance initiator port would be a good starting point.

[sdo]

But you could save quite a bit of money, by just getting one more dual port FC HBA in the appliance, and cabling directly.  This way a SAN switch would not be required.  Less cost on hardware (switch and SFPs) versus one HBA card, no SAN switch port licensing costs, no annual hardware and software maintenance cost for the SAN switch, less to learn, no upgrades (Brocade FabricOS or Cisco CatOS(?) or IOS(?)) to perform, less cabling (four fibre cables instead of six), less racking, less power and cooling, and zero latency for FC frames/packets/data, less to manage, less to monitor.  No zoning required, as the tape drive WWPNs will simply pop-up on the appliance, and the appliance HBA port WWPNs will simply pop-up within the tape library management GUI - i.e. each single initiator and each single target will simply join with each other.  I forget the actual term, sorry, anyway the FC ports at each end will change in to a special point-to-point mode, as opposed to being in a switched fabric mode.

If this NetBackup environment is not expected to grow radically, or even grow beyond it's current size within two years... into more appliances and more tape libraries (probably shared)... then, personally, I wouldn't go the SAN switch route - and I'd go the cable direct route.

You can always add a SAN switch later if the environment grows.  Switching over from direct cabled to zoned fabric would only take a few hours, and would be a doddle to create four single initiator zones, each with one target and one initiator.

N.B: Appliances can only do 'so' much.  Four tape drives (I assume LTO6) is already pushing it.  The official line from Symantec is, I believe, if duplicating from MSDP (de-dupe) storage then no more than two tape drives per appliance.  If duplicating from 'advanced disk' within the appliance then (my opinion here) you should be ok with four tape drives but there's no official guidelines on that as far as I know.   I would suspect that four LTO6 tape drives would be the very uber upper limit, and you wouldn't be looking at adding more tape drives than this.  LTO6 is extremely capable, and very data hungry.

Gosh, the more I think about this, the less I know about your environment, and so the less I should be saying. I have to ask, how much disk storage capacity does the appliance have, and in what form (how many shelves, and what size disks/spindles in the shelves)?  And do you have a design which dictates how that storage will be partitioned?

And I have to ask this too... How did you arrive at four tape drives?  Was it scoped, sized and designed?  Or just purchased straight off?

[jim_dalton]

Brocade switches come with a straightforward web gui in case sdo is scaring you with command line.

If you go for a switch make sure you back up the config once its configured as desired.

We use Broc 300 to knit together storage, tapes, servers but I believe theres a 200 model which might be better value. Jim

[sdo]

@Jim :)

When you've got thousands of ports on each of multiple fabrics... I prefer to carefully plan zoning in advance of the change, and all prepared in notepad as this allows me to carefully check the syntax - this also forces me to have to think about exactly what it is that I'm planning to do, i.e. balancing carefully the distribution of LUNs and initiators and targets, and affords the opportunity to have the plan checked by your colleagues, and allows me to capture the entire session in a PuTTY log with embedded 'date' so I know exactly when something was actually done... in case things go wrong.

Normally my zoning plan would include at lot of 'show' type commands at the start of the plan before getting down to actual zoning, i.e. to carefully check the SAN as a whole, and the switch that I am logged on to, before making any changes whatsoever - which can also be used to capture the original 'config' and all aliases and zones before changing anything.  This way one has something which clearly proves the way things were before anyone made any changes.

We've banned juniors from using the GUI.  They all have to plan in advance, full syntax.  It's just too risky for us to let anyone loose on the GUI.