ADSM-L

Re: Question about DR TSM site

2005-09-12 17:50:15
Subject: Re: Question about DR TSM site
From: "Stapleton, Mark" <mark.stapleton AT BERBEE DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 12 Sep 2005 16:49:43 -0500
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On 
Behalf Of Aaron Durkee
>  We have TSM 5.3.1.4 running on a pseries, AIX 5.3 located in 
>the main data center with most of the servers and a 3584 tape 
>library, site a.
>  We want to install a new pseries running the same version of 
>aix and tsm with a spanking new 3854 at another data center site b.
>  The vision was to have the servers at site a backup to site 
>b, and the servers at site b to backup to site a, cross 
>backups so, when the backup completes in its nature its 
>already off site.  
>  Then we were gonna partition the libraries and generate the 
>copypool at original site for the data.
>  We also have all kinds of toys, like dark fiber, a fibre 
>channel long distance solution, brocade switches, emc clariion 
>at each site and the like.   There are plans to mirror tsm at 
>the aix logical volume level between the sites and share the 
>logically partitioned libraries, also between sites.
>  
>   Ok then,
>   
>What my Director wants to know if anybody out there, rather 
>then having the complexity of fiber channel is simply backing 
>up their clients twice, once to a tsm instance at each site?  
>What pitfalls are seen?  Also, there was an objection to 
>copypool for each instance (four copies of the data) is there 
>anyway to protect against media failure without copypool?

Done all the time.

The easiest way to do this is to make the libraries shared for both TSM
servers. In other words, you've got TSM server A with direct access to
library A and library B, and TSM server B with shared access to library
B and library A. (This assumes that you've got WAN connectivity among
both servers and both libraries.)

Your primary tape pool for each server should reside in whichever
library is local (within the same room or building). The BACKUP STG pool
command should point to a copy storage pool whose volumes reside in the
remote library. So you end up with the following setup:

TSM server A-->primary tape pool in library A
            -->copy tape pool in library B
TSM server B-->primary tape pool in library B
            -->copy tape pool in library A

There is a temptation to set up server-to-server communication instead
to do this, but if you do you have the added complexity of virtual
volumes to deal with, plus the fact that both TSM servers must be up for
virtual volumes to be of any use.

Shared libraries are easy to set up on the 3584, and (as you mentioned)
there is no tape shuffling required for DR purposes. This makes much
more sense than backing up each client twice (once to each server) and
wastes much less tape and fiber bandwidth.

--
Mark Stapleton (stapleton AT berbee DOT com)
IBM Certified Advanced Deployment Professional
  Tivoli Storage Management Solutions 2005
IBM Certified Advanced Technical Expert (CATE) AIX
Office 262.521.5627

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