ADSM-L

Re: direct attached disk (DAS) at a tape library?

2004-09-29 15:33:06
Subject: Re: direct attached disk (DAS) at a tape library?
From: "Stapleton, Mark" <mark.stapleton AT BERBEE DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Wed, 29 Sep 2004 14:34:51 -0500
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On 
Behalf Of Johnson, Milton
>No idea about TSM's LANFREE being a limited use copy of 
>Sanergy.  

It is not.

>My understanding was that the big difference was in 
>the client code so that the meta data goes over the LAN to the 
>TSM server's DB and the actual backup data goes across the SAN 
>directly to the SAN attached tape drive with the TSM server 
>still controlling the tape drive access.  I assumed this was 
>just a case of the TSM server telling the client which tape 
>drive to use and then the client sends the data to the SAN 
>attached tape drive in the same manner the TSM server normally 
>sends data to a SAN attached tape drive.  When the client 
>completes the back-up, it informs the TSM server and the 
>server knows that the tape drive is now free for other usage.
>
>During IBM's presentation on tapeless back-ups they said that 
>if you where going the route of DASD storage using a FILE 
>device class stgpool, you would need the full blown Sanergy 
>application to do a LANFREE back-up.  I would assume that this 
>meant at least two copies of Sanergy, one for the TSM server 
>and one for the client.

If you want a LAN-free backup of SAN-located client data to SAN-based
disk used by the TSM server, you must use SANergy. SANergy creates an
NFS-type mount from target-controlled disk to source-controlled disk,
and initiates a copy of data from source to target. The how-tos are in
the SANergy documentation.

It is **fast**, since the bottleneck in such a transfer is the speed of
the disk bus. Metadata about the client data still travels across the
LAN, but that's a piffle compared to the size of the data itself.

--
Mark Stapleton (stapleton AT berbee DOT com)
Berbee Information Networks
Office 262.521.5627