2 node cluster

[baudinpr]

Hi all,

I plan to configure a 2 node cluster based on 2 Dell servers and a MD3200 DAS (via SAS link).
I'm looking for HA, so I need a quorum disk.
The (stupid) question is: the quorum disk should be used via iSCSI from a VM running in the cluster ?
What happen if the quorum disk fail (example the VM crash) ?
What happen if I don't have a quorum disk ?

Thanks in adavance.
PieroB

 

[baudinpr]

Ok,

I'm going to a 3 nodes solution
I have a question about fensing redundancy.
With 2 stackable switch and interface bonding for cluster management, I have redundancy.
Bat the iDRAC cards are one per server, so in the best scenario with 3 nodes I'll have 2 iDRAC in a switch and the other iDRAC on the other switch.
What happens if the switch with 2 iDRAC connected fails ? Management will be preserved, but fencing ?

Thanks
PieroB

 

[dietmar]

What happens if the switch with 2 iDRAC connected fails ? Management will be preserved, but fencing ?

Such setup is not optimal, because fencing will not work in that case, and all cluster operations will block.

Fencing with iDRAC will also fail if you loose power on a node.

 

[baudinpr]

Thanks Dietmar,

so, what's the optimal setup ?

Thanks
PieroB

 

[tom]

Use an independent fencing hardware, e.g. power fencing (like http://pve.proxmox.com/wiki/Fencing#APC_Switch_Rack_PDU)

(If your fence device is "inside" your server, you cannot fence if your server is powered off.)

 

[dietmar]

so, what's the optimal setup ?

This totally depends on your needs (failure model). Some people can live with such restrictions, others want multiple independent fence devices.

 

[baudinpr]

Thanks Dietmar and Tom,

Tom, ok, but... if the ethernet card of the PDU fails ??

PieroB

 

[dietmar]

Tom, ok, but... if the ethernet card of the PDU fails ??

You can have multiple, redundant fence devices.