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<p>Hi everyone!</p>
<p>I need a sanity check on our Server Quorum Ratio settings to
ensure the maximum uptime for our virtual machines. I'd like to
modify them slightly, but I'm not really interested in
experimenting with live servers to see if what I'm doing is going
to work, but I think that the theory is sound.<br>
</p>
<p>We have a Gluster array of 3 servers containing two Replicate
bricks. <br>
</p>
<p>Brick 1 is a 1x3 arrangement where this brick is replicated on
all three servers. The quorum ratio is set to 51%, so that if any
one Gluster server goes down, the brick is still in Read/Write
mode and the broken server will update itself when it comes back
online. The clients won't notice a thing, while still ensuring
that a split-brain condition doesn't occur. <br>
</p>
<p>Brick 2 is a 1x2 arrangement where this brick is replicated
across only two servers. The quorum ratio is currently also set to
51%, but my understanding is that if one of the servers that hosts
this brick goes down, it will go into read-only mode, which would
probably be disruptive to the VMs we host on this brick.<br>
</p>
<p>My understanding is that since there are three servers in the
array, I should be able to set the quorum ratio on Brick2 to 50%
and the array will still be able to prevent a split-brain from
occurring, because the other two servers will know which one is
offline. <br>
</p>
<p>The alternative of course, is to simply flesh out Brick2 with a
third disk. However, I've heard that 1x2 replication is faster
than 1x3, and we'd prefer that extra speed for this task.<br>
</p>
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