<br><font size=2 face="sans-serif">Greg wrote:</font>
<br><tt><font size=2>>That brought to light a couple of cases where
we don't have a good plan:<br>
>- Squid box failure.</font></tt><font size=2 face="sans-serif"><br>
</font>
<br><font size=2 face="sans-serif">Greg,</font>
<br><font size=2 face="sans-serif">I have a radical idea, and it fits in
the N+1 redundancy. For OLE-Nepal, have three machines:</font>
<br><font size=2 face="sans-serif">1) The primary XS</font>
<br><font size=2 face="sans-serif">2) The primary Squid</font>
<br><font size=2 face="sans-serif">3) The backup machine</font>
<br>
<br><font size=2 face="sans-serif">Now, here's the trick, we make the "backup
machine" have both an XS and Squid implemented on them,</font>
<br><font size=2 face="sans-serif">and with scripts activate one or the
other so the next time it starts up, that is what it runs as. This
simplifies</font>
<br><font size=2 face="sans-serif">the recovery to:</font>
<br><font size=2 face="sans-serif">XS goes down --> tell backup machine
to be "primary XS" and reboot machine (with correct IP addresses)</font>
<br><font size=2 face="sans-serif">Squid goes down --> tell backup machine
to be "primary Squid" and reboot machine (with correct IP addresses)</font>
<br>
<br><font size=2 face="sans-serif">The primary XS and Squid boxes can be
scripted to send updates to the backup box, so that when it</font>
<br><font size=2 face="sans-serif">needs to play one or the other role,
it will have all the latest data.</font>
<br>
<br><font size=2 face="sans-serif">In the event XS goes down and is replaced
by the Backup box, then when the repaired XS comes back,</font>
<br><font size=2 face="sans-serif">it becomes the new backup box.</font>
<br>
<br><font size=2 face="sans-serif">This also supports "scheduled/planned
maintenance", putting in a bigger drive, adding memory, etc.</font>
<br><font size=2 face="sans-serif">One machine can be upgrade while the
other two are getting the job done.</font>
<br>
<br><font size=2 face="sans-serif">While the Squid box may not need as
much memory or processor as the XS box, perhaps it would </font>
<br><font size=2 face="sans-serif">be simpler just to have a standard HW
config for all three boxes so that they are interchangeable. The</font>
<br><font size=2 face="sans-serif">alternative would be to put the weakest
box as Squid, strongest as primary XS, and the third is Backup.</font>
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<td><font size=1 color=#0060a0 face="Microsoft Sans Serif"><b>Tony Pearson</b></font><font size=1 face="Microsoft Sans Serif"><br>
Senior Storage Consultant, IBM System Storage™<br>
Telephone: +1 520-799-4309 | tie 321-4309 | Cell: +1 520 990-8669<br>
email: tpearson@us.ibm.com | GSA: http://tucgsa.ibm.com/~tpearson<br>
Blog: http://www.ibm.com/developerworks/blogs/page/InsideSystemStorage
AKA: 990tony Paravane, eightbar specialist </font></table>
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