Veritas-bu

Re: [Veritas-bu] Storage unit groups are not understood - yes I'mpuzzeld

2008-04-29 00:04:31
Subject: Re: [Veritas-bu] Storage unit groups are not understood - yes I'mpuzzeld
From: "Tharp, Trey" <Trey.Tharp AT allstate DOT com>
To: <veritas-bu AT mailman.eng.auburn DOT edu>
Date: Mon, 28 Apr 2008 22:45:40 -0500
What's the multiplexing # set to on the schedule? Also, "Allow multiple
data streams" is checked on the policies, right?

You can have an unlimited number of policies using a storage unit group
as far as I know. We've got well over 100 policies using a storage unit
group with 2-4 storage units in it and we run over 1000 active jobs to
this storage units.

There are many enablers and limits for multiplexing and multistreaming
that all have to be turned on and turned up for it to work. The lowest
denominator is on the schedule itself, so if a new stream starts, it
will not join a mpx group that's got more jobs active than what it's set
to.

i.e. a schedule with an mpx setting of 4 will not join a storage unit
with Max Drives = 1 and Max MPX = 10 that's got 5 streams running, even
though the storage unit can take 5 more streams.

-Trey

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of fred
fred
Sent: Saturday, April 26, 2008 4:22 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] Storage unit groups are not understood - yes
I'mpuzzeld

In the relms of the Top 20 (or so) misunderstood ....specifically #2.
Storage unit groups are not understood.  (version = 6.5.1)

I'm still puzzled..... If you have policies pointing to the same storage
group with two policies running with the a couple of streams each.  Then
a third starts it ends up by queueing.  The only difference being its
not NT Windows but a Standard Unix policy.
Rentetion time and media pool the same.

Can only a limited number of Policies actually use the storage group at
any one time, even if the retention time and tape pool the same?

Does the same apply  for storage units?

If you have  a stroage unit like below I would expect you could have two
policies writng to it at the same time (with no queueing ) as long as
there less than a total of 10 streams. Policies with media multiplexing
of 10 and same retention and pool.

Storage Unit:
Multiplexing enabled
Maximum concurrent write drives: 1
Maximum streams per drive: 10
I have set it to one as I don't what to multistream to more that two
tapes drives in the storage unit group.

Storage Unit Group (set to "balance load" ) has two storage units of the
above i.e a max of 20 streams i.e it will do twice the work load
of my example  I'm assuming each stream is a "job".   In the manuals
what is a "job" seems to change with context.

Max client streams = 24 (for slow backups of small servers)

Am  I missing anything?

Cheers Fred
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