2 servers 1 cup (or SAN)

[LionelR]

Hi all,
for the moment we have PVE 3.1 running on a single server and supporting 2 VM's (HP DL360 G7). Joining the dark side of the force, we want to buy another server for setting up some HA, and putting the VM's on a SAN (bigger storage, much more VM's coming). So, is it possible without another third server, and much important, is it simple to implement (and optionaly, how)?

Thanks!

 

[mir]

For a 2-server setup to have HA support you will need to use a quorum disk. The quorum disk must be exported as a iSCSI LUN from the SAN (https://pve.proxmox.com/wiki/Two-Node_High_Availability_Cluster#Create_the_Quorum_Disk)

 

[dietmar]

For a 2-server setup to have HA support you will need to use a quorum disk.

AFAIK newer corosync 2.4 does not support quorum disk (correct my if I am wrong), so I guess we should stop suggesting such setup?

 

[mir]

Is this info obsolete? http://people.redhat.com/ccaulfie/docs/Votequorum_Intro.pdf
According to the above quorum disk is not written out but was not available at the time of writing.

 

[spirit]

AFAIK newer corosync 2.4 does not support quorum disk (correct my if I am wrong)

Currently quorum disk is not supported on corosync2

But devs are working on something similar
https://github.com/corosync/corosync/wiki/Design-qdevice

(But I don't think it's already implemented)

 

[mir]

The man page for the code is here: https://github.com/corosync/corosyn...e3d85846/man/votequorum_qdevice_register.3.in

And the todo list:

--------------------------------------
Current priority list for Needle 2.1
--------------------------------------
[...]
* porting of qdisk to votequorum and eventually finalize qdevice API
in votequorum. (Fabio)

So qdisk should be available in 2.4

 

[mir]

See also: https://www.mankier.com/3/votequorum_qdevice_poll

 

[dietmar]

See also: https://www.mankier.com/3/votequorum_qdevice_poll

Well, the interesting part in the article you posted is:

we hope these will mostly remove the need for that pesky qdisk and itscomplicated timings and obscure heuristics options (what were they all about?!).

 

[LionelR]

Hi guys,
do I have to buy another server just for that?

 

[mir]

do I have to buy another server just for that?

If quorum disk is not supported then this will be your only option. If you configure fail-over domains the third server could be very cheap and low power, all required is 64bit capability. If you don't mind using consumer grade hardware a cheap and low power solution could be made using a motherboard based on an Intel Celeron J1900 CPU or an AMD Athlon 5350 in an AM1 socket based motherboard.

 

[LionelR]

Thanks for your responses. How can we know if quorum disk is supported?