Sent from my iPhone

On May 16, 2021, at 2:18 AM, andrei.borzenkov@fujitsu.com wrote:

You can only bring up two nodes if one of them has epsilon. Otherwise no configuration changes are possible and that includes breaking snap mirror.

If those two nodes do have epsilon, it is just normal procedure to failover LIF. After snap mirror break destinations volumes are not renamed - they remain exactly as they are. Nothing special needs to be done when two remaining nodes arrive - they just join cluster normally.

If these two nodes do not have epsilon, your best bet is to wait for the remaining cluster nodes to arrive. I am not aware of possibility to force epsilon in this case. May be it exists, but you certainly need support case to obtain it and any follow up step.

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От: Пользователь Toasters <toasters-bounces@teaparty.net> от имени пользователя John Stoffel <john@stoffel.org>
Отправлено: воскресенье, мая 16, 2021 04:54
Кому: <Toasters@teaparty.net>
Тема: 4 node cluster - only two nodes coming up

Hi all,

We're in the middle of hell, where our 4-node FAS8060 cluster was
shutdown cleanly for a move, but only one pair made it onto the truck
to the new DC. Luckily I have all the volumes snapmirrored between
the two pairs of nodes and their aggregates.

But now I need to bring up the pair that made the trip, figure out
which mirrors are source and which are destination on this pair, and
then break the destination ones so I can promote them to read-write.

This is not something I've practiced, and I wonder that if I have
volume foo, mounted on /foo, and it's snapmirror is volume foo_sm,
when I do the break, will it automatically mount to /foo? I guess
I'll find out later tonight, and I can just unmount and remount.

I think this is all good with just a simple 'snapmirror break ...' but
then when we get the chance to rejoin the other two nodes into the
cluster down the line, I would asusme I just have to (maybe) wipe the
old nodes and rejoin them one at a time. Mostly because by that point
I can't have the original source volumes come up and cause us to lose
all the writes that have happened on the now writeable destination
volumes.

And of course there's the matter of getting epsilon back up and
working on the two node cluster when I reboot it. Along with all the
LIFs, etc. Not going to be a fun time. Not at all...

And of course we're out of support with Netapp. Sigh...

And who knows if the pair that came down won't lose some disks and end
up losing one or more aggregates as well. Stressful times for sure.

So I'm just venting here, but any suggestions or tricks would be
helpful.

And of course I'm not sure if the cluster switches made it down here
yet.

Never put your DC on the second floor if there isn't a second freight
elevator. Or elevator in general. Sigh...

John
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