Re: Moving a 4 node cluster in two pairs?

just to add to Heino: I had a student in one of my courses just lately,
that moved his datacenter some 4-5 km with exactly this setup (4 cluster
switches and good redundant connectivity) and some swing gear, if I
remember correctly, because he didn't have enough capacity to completely
evacuate a pair before the move. Completely non-disruptive, nobody noticed
anything...

Sebastian


sent from my mobile, spellchecker might have messed up...

On Tue, 2 Mar 2021, 19:36 Heino Walther <[email protected]> wrote:

> Hi John
>
>
>
> I’m not sure if this helps…
>
> I am also sure you can get the cluster running with half the nodes.
>
> I am actually migrating between two HA-pairs as we speak.
>
> We choose to setup a link between the nodes with two cluster switches, so
> the two HA-pairs is about 500M apart… (I’m not sure when latency becomes an
> issue)
>
> But what we did was to add the two new nodes (temporary nodes) to the
> existing cluster, and we are then able to use the “vol move” operation to
> move volumes from one HA-pair to another, and of cause also the LIFs.
>
> Works a charm so far.  Huge NFS datastores have been moved with a hitch.
>
> We did a “vol move start” with the “-cutover-action wait” option, which
> does the mirroring but waits until we tell it to do the cut-over… (in a
> service window)
>
> There is however some “dedupe processes” which makes the cut-over very
> slow on larger volumes… it keeps telling us that it is waiting for a dedupe
> process to complete… (both systems are AFFs)…. But after 10-30 minutes it
> completes OK.
>
>
>
> Once we have emptied the source HA-nodes, we will move them to the new DC,
> and do it all over again back to the original system again…
>
>
>
> So far no down time at all, which is nice 😊
>
>
>
> I realize that you may not be a lucky as to where you have to move the
> systems 😉
>
> So drive safely, and if you are running spinning disks, be prepared to
> replace a few as you startup the system 😉
>
>
>
> /Heino
>
>
>
> *Fra: *Toasters <[email protected]> på vegne af John Stoffel <
> [email protected]>
> *Dato: *tirsdag, 2. marts 2021 kl. 19.24
> *Til: *[email protected] <[email protected]>
> *Emne: *Moving a 4 node cluster in two pairs?
>
>
> Guys,
> We're getting ready to move our 4 node FAS8060 cluster to a new data
> center.  As part of our due diligence, we're thinking that we would
> snapmirror the most critical business volumes between the two pairs.
>
> The idea would be that if the truck holding pair A+B doesn't make it
> for some reason, we can still bring up the cluster with nodes C+D and
> still have those snapmirrored volumes available to continue working.
>
> So my questions are:
>
> 1. Can I boot a cluster with half the nodes missing?  I'm sure I
>    can...
>
> 2. Has anyone else had to do this half assed method of shipping DR?
>
> Cheers,
> John
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