>> On Mon, 1 Dec 2008 08:07:53 +0100, Stefan Folkerts <stefan.folkerts AT ITAA 
>> DOT NL> said:

[...]


I haven't yet seen mention of what was the coolest thing (to me) about
the fastback product: 'instant' restore.

The basic idea is, if you restore an entire volume, the whole thing
gets mounted immediately.  Then, TSM starts rattling around restoring
individual files, in whatever order its' normal efficiency
calculations suggest.

-BUT-

if you try to open a file, then it

+ permits the open to succeed, but blocks reads
+ interrupts the ongoing restore stream
+ restores the file you were after.  Unblocks reads.
+ goes back to processing the restore stream


So, for many purposes, the filesystem is back much faster, maybe even
"immediately".  This improvement is exacerbated if you're on FILE
volumes: it may be fast enough that you don't even notice that TSM
hadn't gotten around to restoring that bit yet.

There was more than a little bit of smoke and mirrors, but it -looked-
as though that also worked on a per-message basis for exchange:
i.e. you only pulled down the blocks you needed for the message you
wanted back.  That sounded very very keen.


- Allen S. Rout