TSM LAN free backups

Why would you want to use LAN free? Generally speaking, backing up and restoring over a SAN is much faster that over a LAN, but that really depends on how fast those two items are in your site. Another benefit for traditional TSM is that LAN free avoids clogging up backup disk pools with large backups, as this uses a front end disk pool that is offloaded to tape each day. LAN free is also very suitable for big databases. However many TSM installations do not use tape, or they may use active copy storage pools. So LAN free is not an automatic choice, you need to study the costs and the benefits to see if it will fit into your site. Also, tape drives are finite resource and too much LAN free will quickly use them up.
Assuming you decide to install LAN free, this is how you would do it on AIX.

Connecting the Tape Drives

First you need to organise cabling up your tape drives. If your backups are critical you will need two fiber cards installed in each client for resilience. Then you need them cabled up to your SAN switches and zoned in so your client can acccess the tape drives. It is possible to rename your tape drives to something more meaningful that the rmtnn names that UNIX provides by default, but to do that you need to install an Atape driver, supplied free by IBM. Once you do this, you rename the drives with smitty, or with the chdev command as below. It is best to give your drives a name that contains the WWWN then they are unique. When you rename them, several files will be created in the /dev directory. The device parameter in your path name in TSM must match these names. The chdev command in full is:

 chdev -l rmt0 -a new_name=T_AA02450

Defining the Storage Agent

Define at the TSM Server

Use a comand like the one below to define a storage agent to the TSM server. If you want to look at existing storage agents to see how they are defined, you will find them by using the 'q server' command or the 'other servers' tab in the GUI.

define server nnnnn serverpassword=password hla=x.xx.xx.xx lla=xxxx
    
nnnnn is the name of the storage agent. Each agent name needs to be unique, so come up with a good naming standard. A simple standard that works is nodename_agent.    
password is the password for the storage agent and must match the password supplied in the client definition below    
xx.xx.xx.xx is the ip address (or DNS entry) of the client machine    
xxxx is the port you use in the dsm.sys for the storage agent. The example below uses 1510.    

define the tape paths

To define the tape paths to the TSM server, use commands like

 define path agent.name tape.name SRCT=server destt=drive library=LIBNAME device=/dev/tape_name

If you use alternate pathing, add a '0' onto the end of your tape name in the device parameter above.

Define at the Client

The Storage Agent is usually found in the /opt/tivoli/tsm/StorageAgent/bin/ for TSM 6.1 clients and above, and /usr/tivoli/tsm/StorageAgent/bin/ in TSM 5.5 clients and below. A Storage Agent is basically just a cutdown version of a TSM server with a reduced command set. It needs a dsmsta.opt options file just like a real server and typical values could be as follows.

  Commmethod         tcpipDevconfig          devconfig.statxngroupmax        512enable3590library  yescommtimeout        7200idletimeout        120tcpport            1510

You need to work out what timeout parameters are best for your site. Commtimeout is in seconds and idletimeout in minutes, so they are both set here to two hours. If you are backing up Oracle databases with incremental RMAN, then Oracle can spend some time searching its catalog to workout what needs to be backed up. Without high timeout values the backup could fail, so the numbers above could be reasonable. However this does mean that if you hit a problem you are locking out tape drives for a long time, so smaller values could be more appropriate for standard backups.

Once you have an options file you create the storage agent with the command

 dsmsta setstorageserver myname=nnnn mypasswordpppp myhladdress=nnnservername=TSM1 serverpassword=pppp hla=nnn lla=mmmm

This will create a file called devcongif.sta that contains the above details, with the passwords encrypted. The parameters in the command are

• myname is the name you call your storage agent, the same one you used to define the agent to the TSM server above.
• mypassword is the password for the storage agent and must match the password used when you defined the agent to the server.
• myhladdress is the TCPIP address of the client that is hosting this storage agent
• servername is the name of the TSM server
• serverpassword is the password for the TSM server
• hla is the tcpip address that you use to get to the TSM server, the same one that you use in the dsm.sys file
• lla is the port name that you use to access the TSM server, the tcpport parameter in the dsm.sys file

Next you need to start your storage agent, which you can do by simply typing echo "dsmsta" from the command line. To stop the storage agent, you can log into it using 'dsmadmc -se=storageagentname then typing halt from the command line. Alternatively, just use the UNIX kill command.

Changes to dsm.sys

To use LAN free backups you need to make a few changes to the dsm.sys file. First you need to add a stanza for the storage agent like this, which is used to connect to the storage agent with the dsmadmc command. The node name must not be the one you use for normal backups.

 servername         nodename_agenttcpserveraddress   127.0.0.1tcpport            1510commmethod         tcpip

The tcpserveraddress could be the address of your real server, but it is shown here as the standard IP address of the localhost, as it is just used for internal communication.
The tcpport number does not have to be 1510, but it must match the value you used in dsmsta.opt. I avoid 1500 as that is the server default and like to use 1501 upwards for the webports, so it seems reasonable to standardise all the storage agents at 1510. You must make sure that you do not conflict with any address used by other software on your machine so this standard might not be suitable for you.

Next you need to add some lines to your exisiting backup stanzas like this

 servername         TSM1commmethod         tcpipwebports           1501,0other parms .  lanfreecommmethod  tcpiplanfreetcpport     1510enablelanfree      yesetc

The lanfreetcpport number must match the tcpport in dsmsta.opt and the tcpport in the storage agent stanza

Management Class

Finally you need to create a management class that writes direct to tape. Thebackup section discusses how to do this