ADSM-L

Re: AW: Incremental Forever

2000-05-04 11:04:09
Subject: Re: AW: Incremental Forever
From: Fred Johanson <fred AT MIDWAY.UCHICAGO DOT EDU>
Date: Thu, 4 May 2000 10:04:09 -0500
As the CE explained it, he understood that every 3590B, readonly to ADSM,
required at least two and maybe three passes the first time it was mounted
on a 3590E, once to find the end of the cartridge and once to verify or
rebuild the VCR.  He wasn't sure if the restore was done on this second
pass or on a third.  But the explanation was enough to pacify the
CIO.  However, bare-metal restore is the hot issue, and multiple mounts to
rebuild a harddrive is perceived as a weakness.  Collocation is a solution,
but at quite a cost, since I don't have enough tape capacity for a copypool
for desktops as it is.  It also doesn't make an impression that most
restores done now are of a few files at a time.


At 10:06 AM 5/4/2000 -0400, you wrote:
Did the 3590B --> 3590E conversion cause the slowness?
Or was the slowness caused by something else?
A tape mount should only take a minute or so - the five mounts you
mention can't have caused the four hour delay.

You seem to be saying, "better rethink - maybe need to collocate
everything, even the desktops".
But maybe the slowness you saw in this case has little to do with
collocation-or-not.

Fred Johanson wrote:
>
> At 11:45 PM 5/3/2000 -0400, you wrote:
> >=> On Wed, 3 May 2000 12:26:59 -0400, Lindsay Morris <lmorris AT OPENMIC DOT 
COM>
> >said:
> >
> > > And another thing  :-}   ----
> >
> > > In the event of a site disaster, won't there be lots of tape
contention?
> > > [...]  (Unless you collocate your copy pool - not recommended.)
> >
> >Why is colocation not reccommended?  Certainly there are situations
for which
> >it's a pain, and pointless.   But in general?
> >
> >
> > > Backup sets solves this one too.  But you'd have to make backup sets of
> > > EVERYTHING on a regular basis.... Ouch!
> >
> >Think about this: maintaining colocation is functionally nearly
equivalent to
> >making backup sets of everything, all the time, except that you remove the
> >intermediate step of mixing all the data together in the fist place.
> >
> >
> >As always, plan this out:  How long can you afford to take to recover?
> >
> >At UF, Our campus authentication servers are worth the effort to colocate,
> >ditto campus mail servers, web hosts, etc.
> >
> >Workstations of Data Center staff aren't worth it.
> >
> >
> >
> >- Allen S. Rout
> >- NERDC TSM Admin
>
> Allen, I heartily agree with this, and so did my management, until the day
> the CIO restored EUDORA on his desktop, the day after we had switched from
> 3590Bs to 3590Es.  Four hours and five mounts later, it was recommended
> that I rethink the scheme.  I'm still thinking.
>
> Fred Johanson
> System Administrator, ADSM
> S.E.A.
> University of Chicago
> 773-702-8464

--
Mr. Lindsay Morris
Certified: AIX,ADSM, TSM, HACMP,SP
Gresham Enterprise Storage
lmorris AT openmic DOT com
606-253-8000

Fred Johanson
System Administrator, ADSM
S.E.A.
University of Chicago
773-702-8464
<Prev in Thread] Current Thread [Next in Thread>