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Add CTL HA report from mav

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Benjamin Kaduk 2015-10-17 21:08:46 +00:00
parent 7e42d50326
commit 9e719d1efe
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=47606
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en_US.ISO8859-1/htdocs/news/status/report-2015-07-2015-09.xml
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@ -2299,4 +2299,60 @@
</help>
</project>
<project cat='proj'>
<title>High Availability clustering in CTL</title>
<contact>
<person>
<name>
<given>Alexander</given>
<common>Motin</common>
</name>
<email>mav@FreeBSD.org</email>
</person>
</contact>
<body>
<p>CAM Target Layer (CTL), when originally developed by
Copan/SGI, had support for High Availability clustering.
Unfortunately, significant portions of the HA code were never
published with the main body of the source code. Now, the missing
part has been reimplemented from scratch and fixed/improved.</p>
<p>This code supports dual-node HA with Asynchronous LUN Unit
Access (ALUA) in four modes:</p>
<ul>
<li>Active/Unavailable without interlink between nodes, where
the secondary node can report nothing except its presence.</li>
<li>Active/Standby with secondary node handling only basic LUN
discovery and reservation, synchronizing state and command
execution with the primary node through the interlink.</li>
<li>Active/Active with both nodes processing commands and
accessing the backing storage, synchronizing state and command
execution with the primary node through the interlink.</li>
<li>Active/Active with secondary node having no backing storage
access, but instead working as a proxy, transfering all commands
to the first node for execution through the interlink.</li>
</ul>
<p>In the case of lost interlink connectivity to primary node,
the secondary node falls into the Transitioning state, which is
like Unavailable and can't answer most requests, but makes the
initiator wait for recovery or cluster failover.</p>
<p>CTL also got a large number of other improvements, including
support for emulation of CD/DVD drives and removable disks,
live LUN reconfiguration, etc.</p>
<p>The code is committed to &os; head and was recently merged to
stable/10 branch.
</p>
</body>
<sponsor>
iXsystems, Inc.
</sponsor>
</project>
</report>