Wonderful, it doesn't sound too bad then, I will be using three nodes with Kubernetes. Thanks!
On Fri, 9 Aug 2019, 13.45 Roland Kammerer, <[email protected]> wrote: > On Thu, Aug 08, 2019 at 10:41:37PM +0300, Vito Botta wrote: > > Hi, > > > > at the moment I am testing with 3 nodes that have 4 cores and 16 GB of > > ram, and all works great. However since DRBD/Linstor have very little > > overhead compared to other storage products I've tried with > > Kubernetes, I was wondering whether 2 cores and 8 GB of ram would be > > sufficient? > > LINSTOR/DRBD are not that resource hungry. Java is a but, but Rene got > some pretty nice results with some minimal configurations. Rene? > > > Also, if I have three servers with volumes being replicated, how can I > > avoid downtime when upgrading whenever a new release is out? > > That depends a bit what you want to update: > > The really nice thing about DRBD and LINSTOR are that the control plane > is separated from the data plane. Which means you shut down LINSTOR > completely and your data is still up, because DRBD continues to > replicate data. So updating LINSTOR is easy, just do it :) > > If you need to update DRBD (i.e., the kernel modules), then you > basically do this: > - move all resources away from the node you want to update (i.e, no DRBD > resource is Primary anymore) > - drbdadm down all > - rmmod > - upgrade > > And this then you do the same for the next node. We are very careful > that you can have mixed DRBD version until you finally upgraded your > last storage node. Obviously you need to have at least 2 storage nodes, > if you only have one diskful and one diskless node, then yeah, you will > have downtime. And maybe you want to first provide "over redundancy" via > an additional diskful replica, or you are fine that your N times > redundant resource is only N-1 during you upgrade your storage. But that > all depends on your use case. > > The important thing is that data and control plane. > > Best, rck > _______________________________________________ > Star us on GITHUB: https://github.com/LINBIT > drbd-user mailing list > [email protected] > http://lists.linbit.com/mailman/listinfo/drbd-user >
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