LAN free backup means that data goes from the client to the storage device via
fibre channel. Only "meta data", the overhead associated with the backup
application travel between the client and backup server. In a Server Free backup
environment, the device which provides the interface between the SCSI attached
storage device and the fibre channel attached Storage server also has a bit more
smarts and will receive the data from the client and control the storage device.
The server issues meta data commands to the interface device but there is a big
reduction in the amount of data that the server needs to handle.
George Lesho
Storage/System Admin
AFC Enterprises
Eliza Lau <lau AT VTCAT.CC.VT DOT EDU> on 04/18/2001 01:44:55 PM
Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
cc: (bcc: George Lesho/Partners/AFC)
Fax to:
Subject: Re: What is the diff between LAN-free and Server-Free backups
Seth,
I am reading the manual "TSM Managed System for SAN Storage Agent User's Guide"
GC35-0434-00. In the Overview, it talks about the "LAN-free data movement".
"Use of the Managed System for SAN feature requires the installation of a
storage agent on the client system. The storage agent communicates with
the server to obtain and store database information and to coordinate device
and volume access. The server determines if the client is requesting
access to storage for which the client has a SAN path defined. If a SAN
path is defined, the client (via the storage agent) transfers data on that
path." ... "The client, via the storage agent, writes the backup data
directly to the device over the SAN."
If I read this correctly, data doesn't have to channel through the server
then to the backup device via the SAN. The client transmits only library
control metadata to the server, such as policy information, etc. If the
client's data is on the SAN. It can move from the SAN attached storage to
the SAN attached 3494. So how is this LAN-free backup different from
server free backup?
Eliza
>
> Eliza,
> The difference is that in a LAN free backup, the data moves from the
> storage to the server then to the backup device via the SAN. This requires
> the server to spend IO cycles processing the files for backup. In a server
> free backup, the data moves from one storage device in the SAN to another
> without going through the server. In other words, the SAN knows where the
> data is and where it is going and handles the transport without the
> assistance of the client node.
> Seth Forgosh
>
> -----Original Message-----
> From: Eliza Lau [mailto:lau AT VTCAT.CC.VT DOT EDU]
> Sent: Wednesday, April 18, 2001 1:56 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: What is the diff between LAN-free and Server-Free backups
>
>
> Hi,
>
> We are looking into LAN-free backup through a SAN attached 3494. Someone
> on the list just mentioned Server-free backup. What is Server-free backup
> and
> how is it different from LAN-free?
>
> With LAN-free backup, is it possible for SAN attached clients to backup to
> SAN attached disk pools and then migrate to SAN attached 3494 (3590E tape
> drives)?
>
> Eliza Lau
> Virginia Tech Computing Center
> lau AT vt DOT edu
>
>
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