Linux loves DRBD, DRBD loves Linux!!

FATeknollogee

Copied from @LINBIT twitter feed...
https://twitter.com/linbit/status/929033436437852160
Did you know that built into your #Linux OS is everything you need to replace your shared #storage? #DRBD_SDS #DRBD http://ow.ly/ZxEW30guRef

edit: moved my question to another post

scottalanmiller

LOL, yes I did. And DRBD watches the community, too :)

FATeknollogee

Question: Since it's built-in, why aren't we seeing more use of this (in the ML community)?

scottalanmiller

@fateknollogee said in Linux loves DRBD, DRBD loves Linux!!:

Question: Since it's built-in, why aren't we seeing more use of this (in the ML community)?

Not much need for it since it is part of Linux and you almost never do this kind of network RAID at the OS level. XenServer explicitly doesn't support it. Leaving it only a potential on KVM, pure Xen, or unsupported XenServer setups. Given how incredibly rare the need for HA is in the real world, that already moves us to a tiny number of potential use cases.

Then on top of that, DRBD is bundled into other products. So most people using it with XS, for example, do so via HA-Lizard.

On top of that, it competes with other things like Starwind, so it is not the only free player in the space.

After all that... DRBD is a great technology that I've been promoting for a decade. But it is limited to two node systems, and requires a lot of expertise.

FATeknollogee

I thought DRBD 9.x supports multi-node?

https://www.linbit.com/en/drbd-vs-ceph/
Moreover, DRBD-9.x supports multiple peer nodes, meaning one peer might be a synchronous mirror in the local datacenter while another secondary might be an asynchronous mirror in a remote site.

scottalanmiller

@fateknollogee said in Linux loves DRBD, DRBD loves Linux!!:

I thought DRBD 9.x supports multi-node?

https://www.linbit.com/en/drbd-vs-ceph/
Moreover, DRBD-9.x supports multiple peer nodes, meaning one peer might be a synchronous mirror in the local datacenter while another secondary might be an asynchronous mirror in a remote site.

Still a mirror system. So not scale out. It's only useful for two node clusters. No one makes three way mirror clusters.

scottalanmiller

That blog post is wrong, it says that DRBD must be active/passive. But it has offered active/active for some time.

https://docs.linbit.com/doc/users-guide-83/s-dual-primary-mode/