PVE 4.3 - DRBD best practices?

[bkraegelin]

First, let me thank for this great new version.

After installing from scratch I see, that my disk is formatted with one large partition, which is used for lvm. I have three LVs, root, swap and data.

To build a HA cluster of 2 nodes I want to use DRBD for my storage. I don't want to change too much, so I ask for best practices.

• Should I use this already allocated LVM-Thin named data as backing device for DRBD?
  (I already have it removed from the web interface.)
• On top of the new DRBD storage, should I create a LVM-Thin for Images and Container?
• Is there a better (recommended) way? Perhaps (LVM-Thin over DRBD over LVM) or (LVM over DRBD over LVM-Thin)?

Any thoughts about reliability, performance, anything else?

Thanks for any help.
Birger

 

[fabian]

there is no HA with two nodes and DRBD9 is only a technology preview in PVE 4..

 

[bkraegelin]

So, would you recommend to throw in a third node to get HA?
Even if this third node would not be strong enough to hold disks and run VMs?
(Perhaps using something like https://www.zotac.com/de/product/mini_pcs/zbox-ci323-nano, I have laying around here.)

Still my question:

• Best Practice for configuring DRBD?

Thanks
Birger

 

[fabian]

yes you can use a third small node for tie-braking / quorum purposes in PVE, but you still have a two node / replica DRBD cluster which might lead to split brain or other failure situations. there is no best practice for DRBD9 in PVE - it's not recommended for production use as it's a technology preview, and there is no support from Proxmox for it.

 

[bkraegelin]

Just again...

There is loadbalanced HA and failover HA. For the latter a two node DRBD storage is sufficient.

And I asked for DRBD best practice, not necessarily DRBD9.

Thanks,
Birger

 

[fabian]

there is no integration for DRBD8 in PVE 4, there is only the technology preview of DRBD9. I won't repeat myself further, if you think that a two node (DRBD) cluster works for you, I wish you good luck.

 

[Pegasus]

Is DRBD9 still considered a technology preview since your last comment, @fabian?

 

[dietmar]

Is DRBD9 still considered a technology preview since your last comment

All DRBD9 packages are now maintained by Linbit, so please use packages from them directly. Also, I guess it is best to ask such questions directly on the DRBD user list.