Thanks for the reply Richard...

I'm not considering doing anything unsavvy to get this data back --
I'm using TSM Clients, and the platters must remain in the jukebox so
that the data is accessible by end users at the same time this
extraction is going on.  My goal is to select all data from a single
filespace, on a single side of the platter at a time, then move to
the next filespace with data on the same side of that same platter,
and so on, to avoid the issue of flopping the platter around, back
and forth repeatedly, for each filespace, eating up valuable time,
and incurring substantial wear-and-tear on a system that is being
decommissioned due to its age and fragility.

I'm figuring that doing a query that simply tells me which side of
the platter the data is on, or which offset from the beginning of the
disk (and determining which side it's on by saying a number is
greater than or less than a particular block that represents the
half-way mark) will enable me to do things that much faster.

I'm trying to avoid a scenario where I have to make a backup
storagepool, for several TB of data, then mark platters as being
destroyed in order to make retrievals efficient, then copying that as
I perform my extraction.  I simply don't have that much spare disk
lying around.  =)

-JD.


At 7:16 AM -0400 10/15/05, Richard Sims wrote:

Yes, TSM keeps track of where files are on media, but that info is
not exposed to customers. In any case, you should not consider
attempting physical retrieval of TSM-stored data without TSM due to
factors such as any specialized methods by which TSM may have stored
the data (which are proprietary and publicly undefined, including
Aggregation) and complications such as files spanning volumes.

The most straightforward course of action is to proceed as you have
been: get a list of files by volume and then perform Retrieve in that
order.  Remember that the important thing here is the veracity of the
retrieved data, with speed being secondary.  More quickly obtaining
data which is questionable is not a worthy goal.

   Richard Sims

On Oct 14, 2005, at 6:22 PM, Justin Derrick wrote:

 Hi TSMers...

 I'm working on a project to extract archived data from almost 2000
 optical platters.  The data needs to come out of TSM temporarily, be
 reprocessed, and eventually, loaded back into TSM.  The problem is, I
 want to do this in the most efficient way possible, and I'm having a
 little trouble.

 At this point in time, I'm getting the contents of individual volumes
 with a select statement, similar to a 'query content'.  The only
 catch is, I want to read all the files on one side of the platter
 before switching it over to prevent the library from flopping
 platters back and forth, which eats into the aggregate transfer speed.

 Are their 'secret' tables or columns inside TSM that can tell me what
 the exact location of a file on a platter is?  How does TSM know when
 it's mounting a platter if it needs to be flipped over for a
 retrieval?

 Any assistance, information, guidance, etc. will be greatly
 appreciated.

 Have a great weekend!

 -JD.