Veritas-bu

[Veritas-bu] Can SAN Media Servers share tapes?

2003-09-26 13:38:01
Subject: [Veritas-bu] Can SAN Media Servers share tapes?
From: scott.kendall AT abbott DOT com (scott.kendall AT abbott DOT com)
Date: Fri, 26 Sep 2003 12:38:01 -0500
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you can force the read from another server in regular restore activities 
using bpimage to modify the catalog, the force restore media server option 
or the failover media server restore option.

you could look at using Storage Unit Groups and having the SAN media 
server's STU be the highest priority in the list, but then use another 
media server's STU if necessary.  just make sure your max number of jobs 
per client is not larger than the number of drives x mpx available in the 
SAN media server's STU or you'll always use both STUs (SAN media server 
and LAN), which is probably not what you want (assuming schedule's mpx are 
high enough and all streams from the media server are using the same 
retention, otherwise, you'll have to factor that in as well).


- Scott





"Donaldson, Mark" <Mark.Donaldson AT experianems DOT com>
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
09/25/2003 10:29 AM

 
        To:     "'Gardner, Jesse'" <Jesse.Gardner AT storaenso DOT com>, 
"'veritas-bu AT mailman.eng.auburn DOT edu'" <veritas-bu AT mailman.eng.auburn 
DOT edu>
        cc: 
        Subject:        RE: [Veritas-bu] Can SAN Media Servers share tapes?


Your "light bulb" moment is correct.  Each media server keeps its own 
media
database so once a tape is assigned to a media server, no other media 
server
can use it.  For duplication activities, there's the ability to force the
read from another server but regular backup/restore activities don't 
support
this.

The upcoming v5.0 doesn't fix this but on the futures list is a 
consolidated
media database, per Dave Little, so the problem will eventually be fixed.
It'll also solve a failover problem for media servers.

-M

-----Original Message-----
From: Gardner, Jesse [mailto:Jesse.Gardner AT storaenso DOT com]
Sent: Thursday, September 25, 2003 7:06 AM
To: 'veritas-bu AT mailman.eng.auburn DOT edu'
Subject: [Veritas-bu] Can SAN Media Servers share tapes?


Scenario:

One SAN-attached HP LTO Library.
The Master server is also the Robotic Control Host.
Five other SAN Media Servers share the library.
Each of these servers has their own policy, to back themselves up with 
their
own storage unit.
There are (for the example) 5 tapes in the library, all in one volume 
pool.
Each of the above policies uses the volume pool.

Last night I noticed that one of the servers was getting "unable to 
allocate
new media, storage unit has none available".  Available_Media shows that 
all
five tapes are "Active" and not even close to capacity.  Then the cartoony
lightbulb went on above my head.  Once a media server uses a tape, other
media servers can't write to them.  In a way, it kind of makes sense.

Is there any way around this?  Can two of my SAN Media Servers write to a
single tape?

Thanks,
Jesse
_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
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_______________________________________________
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<br><font size=2 face="Arial">you can force the read from another server in 
regular restore activities using bpimage to modify the catalog, the force 
restore media server option or the failover media server restore option.</font>
<br>
<br><font size=2 face="Arial">you could look at using Storage Unit Groups and 
having the SAN media server's STU be the highest priority in the list, but then 
use another media server's STU if necessary. &nbsp;just make sure your max 
number of jobs per client is not larger than the number of drives x mpx 
available in the SAN media server's STU or you'll always use both STUs (SAN 
media server and LAN), which is probably not what you want (assuming schedule's 
mpx are high enough and all streams from the media server are using the same 
retention, otherwise, you'll have to factor that in as well).</font>
<br>
<br>
<br><font size=2 face="Arial">- Scott</font>
<br>
<br>
<br>
<br>
<table width=100%>
<tr valign=top>
<td>
<td><font size=1 face="sans-serif"><b>&quot;Donaldson, Mark&quot; 
&lt;Mark.Donaldson AT experianems DOT com&gt;</b></font>
<br><font size=1 face="sans-serif">Sent by: veritas-bu-admin AT 
mailman.eng.auburn DOT edu</font>
<p><font size=1 face="sans-serif">09/25/2003 10:29 AM</font>
<br>
<td><font size=1 face="Arial">&nbsp; &nbsp; &nbsp; &nbsp; </font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; To: &nbsp; 
&nbsp; &nbsp; &nbsp;&quot;'Gardner, Jesse'&quot; &lt;Jesse.Gardner AT storaenso 
DOT com&gt;, &quot;'veritas-bu AT mailman.eng.auburn DOT edu'&quot; 
&lt;veritas-bu AT mailman.eng.auburn DOT edu&gt;</font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; cc: &nbsp; 
&nbsp; &nbsp; &nbsp;</font>
<br><font size=1 face="sans-serif">&nbsp; &nbsp; &nbsp; &nbsp; Subject: &nbsp; 
&nbsp; &nbsp; &nbsp;RE: [Veritas-bu] Can SAN Media Servers share 
tapes?</font></table>
<br>
<br>
<br><font size=2 face="Courier New">Your &quot;light bulb&quot; moment is 
correct. &nbsp;Each media server keeps its own media<br>
database so once a tape is assigned to a media server, no other media server<br>
can use it. &nbsp;For duplication activities, there's the ability to force 
the<br>
read from another server but regular backup/restore activities don't support<br>
this.<br>
<br>
The upcoming v5.0 doesn't fix this but on the futures list is a consolidated<br>
media database, per Dave Little, so the problem will eventually be fixed.<br>
It'll also solve a failover problem for media servers.<br>
<br>
-M<br>
<br>
-----Original Message-----<br>
From: Gardner, Jesse [mailto:Jesse.Gardner AT storaenso DOT com]<br>
Sent: Thursday, September 25, 2003 7:06 AM<br>
To: 'veritas-bu AT mailman.eng.auburn DOT edu'<br>
Subject: [Veritas-bu] Can SAN Media Servers share tapes?<br>
<br>
<br>
Scenario:<br>
<br>
One SAN-attached HP LTO Library.<br>
The Master server is also the Robotic Control Host.<br>
Five other SAN Media Servers share the library.<br>
Each of these servers has their own policy, to back themselves up with their<br>
own storage unit.<br>
There are (for the example) 5 tapes in the library, all in one volume pool.<br>
Each of the above policies uses the volume pool.<br>
<br>
Last night I noticed that one of the servers was getting &quot;unable to 
allocate<br>
new media, storage unit has none available&quot;. &nbsp;Available_Media shows 
that all<br>
five tapes are &quot;Active&quot; and not even close to capacity. &nbsp;Then 
the cartoony<br>
lightbulb went on above my head. &nbsp;Once a media server uses a tape, 
other<br>
media servers can't write to them. &nbsp;In a way, it kind of makes sense.<br>
<br>
Is there any way around this? &nbsp;Can two of my SAN Media Servers write to 
a<br>
single tape?<br>
<br>
Thanks,<br>
Jesse<br>
_______________________________________________<br>
Veritas-bu maillist &nbsp;- &nbsp;Veritas-bu AT mailman.eng.auburn DOT edu<br>
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu<br>
_______________________________________________<br>
Veritas-bu maillist &nbsp;- &nbsp;Veritas-bu AT mailman.eng.auburn DOT edu<br>
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu<br>
</font>
<br>
<br>
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