Point well taken Steve. Your classification of the nature of the
data is basically correct except for a twist. On the day the data is
written, it is extracted by other programs that analyze the data to spot
flaws and trends in the manufacturing process. Depending on what it finds,
they may then need to delve deeper into the data to analyze and fix
production flaws. So their argument is that without that data online, they
have no idea if the chips we manufactured a couple of hours ago are good or
not.

        True, that after a couple of days the data is infrequently accessed,
and after about a week, the data is rarely accessed, that's why they delete
it after 30 days. But restoring just the files that were newly backed up the
night before is not possible... is it? I don't think a point in time restore
will do that...

        I like the idea of renegotiating the SLA (service level agreement)
with the customer so that their expectations are set and my butt is covered.
Thanks for the advice.

Thanks,
Ben Bullock
UNIX Systems Manager


> -----Original Message-----
> From: Steve Harris [mailto:Steve_Harris AT HEALTH.QLD.GOV DOT AU]
> Sent: Tuesday, February 20, 2001 4:43 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: Performance Large Files vs. Small Files
>
>
> Ben
> >>> bbullock <bbullock AT MICRON DOT COM> 21/02/2001 8:21:34 >>>
> >>>Big Snip
>         This one nightmare host now has over 20 million files (and an
> unknown number of directories) across 10 filesystems. We have
> found from
> experience, that any more than about 500,000 files in any
> filesystem means a
> full filesystem restore would take many hours. Just to
> restore the directory
> structure seems to take a few hours at least. I have told the
> admins of this
> host that it is very much unrecoverable in it's current
> state, and would
> take on the order of days to restore the whole box.
>
>         They are disappointed that an "enterprise backup
> solution" can't
> handle this number of files any better. They are willing to
> work with us to
> get a solution that will both cover the daily "disaster
> recovery" backup
> need for the host and the long term retentions they desire.
> >>> remainder snipped
>
> I would debate whether the host is "unrecoverable".  It seems
> that this data is write once/read seldom in nature.  In that
> case, in the event of a disaster the priorities are
> 1. get the server back to the state where it can write more files
> 2. get back any individual required file in reasonable time
> TSM can provide both of those objects.  If a full restore is
> required it *can* be spread over days because most of the
> data will never be needed.  You will of course need to
> negotiate wth your users exactly what is urgent and needs to
> be restored immediately and maybe have some canned macro to
> do this in the heat of an emergency.
>
> Regards
>
>
> Steve Harris
> AIX and ADSM Admin
> Queensland Health, Brisbane Australia
>