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List: veritas-ha
Subject: Re: [Veritas-ha] SG Failover&Failback Query
From: "Tom Stephens" <tom_stephens () symantec ! com>
Date: 2006-09-03 18:11:05
Message-ID: 39310EC65ADF75458980739A2810901E02A79F55 () svlxchcln2 ! enterprise ! veritas ! com
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Munish,
There's no concept of a primary/secondary node for a SG.
All nodes listed in the SystemList of the SG are just considered as
potential fail over targets in the event of a fault. There are some
factors (such as precedence) that help the in the fail over target
selection, but that's about it.
As for when Freeze is typically used; let's expound upon
your example. Say SGA is online on SysB, as you are doing maintenance
on SysA. The maintenance may take some time, and during the course of
the maintenance, you may need to reboot SysA several times. Assuming
that this is only a two node cluster, then even in the event of a
failure during this maintenance period, you would not want SGA to fail
over to SysA.
Another case where Freeze is used frequently is when the
application owners need to perform some sort of maintenance on SGA.
(Say for example, they need to do some changes to the app which may
require to take it offline and then online again). During this time,
you wouldn't want to have a fault cause a failover, nor have VCS restart
the application if it detects that the application went down (as the
developers may have done this manually).
Hope this explains it a bit more.
Tom
_____
From: Munish Dhawan [mailto:munishdh@yahoo.com]
Sent: Sunday, September 03, 2006 7:00 PM
To: Tom Stephens; Veritas-ha@mailman.eng.auburn.edu
Subject: RE: [Veritas-ha] SG Failover&Failback Query
Tom,
Thanks for clearing the doubt.I have just another query in the same
case, what is the Role of SG Freeze here.
I mean, why we do freezing of SG, what I understand is We Freeze the SG,
so that the SG(now online on SysB) won't failover automatically to the
Primary node(SysA), if the SysA again became UP.
Just want to Know is there any concept of Primary/secondary node for SG.
Thanks in Advance.
Tom Stephens <tom_stephens@symantec.com> wrote:
Munish,
If, after you brought up SysA, SGA failed back over
to it you would incur an outage. It's the position of VCS to try and
maintain the highest availability of your application. As a result, it
will not fail back to a server automatically like this. If SysB faults
for some reason, then it would just use SysA as a fail over target.
The same would occur if the system were to panic
instead of reboot.
Tom
_____
From: veritas-ha-bounces@mailman.eng.auburn.edu
[mailto:veritas-ha-bounces@mailman.eng.auburn.edu] On Behalf Of Munish
Dhawan
Sent: Sunday, September 03, 2006 2:50 PM
To: Veritas-ha@mailman.eng.auburn.edu
Subject: [Veritas-ha] SG Failover&Failback Query
Hi ,
SysA and SysB in cluster for SGA Vcs=3.5 solaris 8
attributer for SGA - System List SysA 0 SysB 1
Autofailover =1
Parallel =0
Question is :- Initally SGA is online on SysA and offline on
sysB. I Shutdown SysA for maintenance , SGA failover successfully to
sysB,Now after Maintenace I boot the SysA, SGA should failback to
SysA(Primary node for SGA),but its not happening. Its still online on
SysB.
Please Let me now why failback is not happening.
What Would happen If instead of Shutdown, a panic reboot occur
on sysA.
Thanks in Advance
Thanks & Regards,
Munish Dhawan
_____
Get your email and more, right on the new Yahoo.com
<http://us.rd.yahoo.com/evt=42973/*http:/www.yahoo.com/preview>
Thanks & Regards,
Munish Dhawan
_____
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Business
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<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Munish,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> \
There’s no concept of a primary/secondary node for a SG. All nodes listed \
in the SystemList of the SG are just considered as potential fail over targets in the
event of a fault. There are some factors (such as precedence) that help
the in the fail over target selection, but that’s about \
it.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> \
As for when Freeze is typically used; let’s expound upon your example. \
Say SGA is online on SysB, as you are doing maintenance on SysA. The
maintenance may take some time, and during the course of the maintenance, you
may need to reboot SysA several times. Assuming that this is only a two
node cluster, then even in the event of a failure during this maintenance
period, you would not want SGA to fail over to SysA. \
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> \
Another case where Freeze is used frequently is when the application owners need to
perform some sort of maintenance on SGA. (Say for example, they need to
do some changes to the app which may require to take it offline and then online
again). During this time, you wouldn’t want to have a fault cause a
failover, nor have VCS restart the application if it detects that the
application went down (as the developers may have done this manually). \
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> \
Hope this explains it a bit more.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> \
Tom<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Munish Dhawan
[mailto:munishdh@yahoo.com] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, September 03, 2006
7:00 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Tom Stephens;
Veritas-ha@mailman.eng.auburn.edu<br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Veritas-ha] SG
Failover&Failback Query</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Tom,<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thanks for clearing the doubt.I have just another query in the same
case, what is the Role of SG Freeze here.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I mean, why we do freezing of SG, what I understand is We Freeze the
SG, so that the SG(now online on SysB) won't failover
automatically to the Primary node(SysA), if the SysA again
became UP.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Just want to Know is there any concept of Primary/secondary node for
SG.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thanks in Advance.<br>
<b><i><span style='font-weight:bold;font-style:italic'>Tom Stephens
<tom_stephens@symantec.com></span></i></b> wrote:<o:p></o:p></span></font></p>
</div>
<blockquote style='border:none;border-left:solid #1010FF 1.5pt;padding:0in 0in 0in \
4.0pt; margin-left:3.75pt;margin-top:5.0pt;margin-bottom:5.0pt'>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Munish,<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>
If, after you brought up SysA, SGA failed back over to it you would incur an
outage. It’s the position of VCS to try and maintain the highest
availability of your application. As a result, it will not fail back to a
server automatically like this. If SysB faults for some reason, then it
would just use SysA as a fail over target. <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>
The same would occur if the system were to panic instead of reboot. \
<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>
Tom<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabIndex=-1>
</span></font></div>
<div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
veritas-ha-bounces@mailman.eng.auburn.edu
[mailto:veritas-ha-bounces@mailman.eng.auburn.edu] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Munish Dhawan<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, September 03, 2006
2:50 PM<br>
<b><span style='font-weight:bold'>To:</span></b>
Veritas-ha@mailman.eng.auburn.edu<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Veritas-ha] SG \
Failover&Failback Query</span></font><o:p></o:p></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hi ,<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>SysA and SysB in cluster for SGA Vcs=3.5 solaris \
8<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> attributer for
SGA - System List SysA 0 SysB 1<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> \
Autofailover =1<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> \
Parallel =0<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Question is :- Initally SGA is online on SysA and offline on sysB.
I Shutdown SysA for maintenance , SGA failover successfully to
sysB,Now after Maintenace I boot the SysA, SGA should failback to SysA(Primary
node for SGA),but its not happening. Its still online on \
SysB.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Please Let me now why failback is not happening.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>What Would happen If instead of Shutdown, a panic reboot occur on \
sysA.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thanks in Advance<o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
Thanks & Regards,<br>
Munish Dhawan<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font></p>
</div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=1 width="100%" align=center>
</span></font></div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Get your email and more, right on the <a
href="http://us.rd.yahoo.com/evt=42973/*http:/www.yahoo.com/preview">new
Yahoo.com</a> <o:p></o:p></span></font></p>
</div>
</blockquote>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<br>
Thanks & Regards,<br>
Munish Dhawan<o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> \
<o:p></o:p></span></font></p>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=1 width="100%" align=center>
</span></font></div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Get your own <a
href="%20http://us.rd.yahoo.com/evt=43290/*http:/smallbusiness.yahoo.com/domains">web
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