Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 4/22/2017 11:51 PM, Andrei Borzenkov wrote: As a real life example (not Linux/pacemaker) - panicking node flush eddisk buffers, so it was not safe to access shared filesystem until this was complete. This could take quite a lot of time, so without agent on *surviving* node(s) that monitors

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 23/04/17 12:51 AM, Andrei Borzenkov wrote: > 22.04.2017 23:33, Dmitri Maziuk пишет: >> On 4/22/2017 12:02 PM, Digimer wrote: >> >>> Having SBD properly configured is *massively* safer than no fencing at >>> all. So for people where other fence methods are not available for >>> whatever reason,

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

22.04.2017 23:33, Dmitri Maziuk пишет: > On 4/22/2017 12:02 PM, Digimer wrote: > >> Having SBD properly configured is *massively* safer than no fencing at >> all. So for people where other fence methods are not available for >> whatever reason, SBD is the way to go. > > Now you're talking. IMO

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 4/22/2017 12:02 PM, Digimer wrote: Having SBD properly configured is *massively* safer than no fencing at all. So for people where other fence methods are not available for whatever reason, SBD is the way to go. Now you're talking. IMO in a 2-node cluster, a node that kills itself in

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 22/04/17 04:39 AM, Andrei Borzenkov wrote: > 22.04.2017 11:31, Klaus Wenninger пишет: > I wonder how SBD fits into this discussion. It is marketed as stonith agent, but it is based on committing suicide so relies on well-behaving nodes. Which we by definition cannot trust to

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

22.04.2017 11:31, Klaus Wenninger пишет: >>> I wonder how SBD fits into this discussion. It is marketed as stonith >>> agent, but it is based on committing suicide so relies on well-behaving >>> nodes. Which we by definition cannot trust to behave well, otherwise >>> we'd not need stonith in

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 04/22/2017 09:20 AM, Digimer wrote: > On 22/04/17 03:05 AM, Andrei Borzenkov wrote: >> 18.04.2017 10:47, Ulrich Windl пишет: >> ... Now let me come back to quorum vs. stonith; Said simply; Quorum is a tool for when everything is working. Fencing is a tool for when things go

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

18.04.2017 10:47, Ulrich Windl пишет: ... >> >> Now let me come back to quorum vs. stonith; >> >> Said simply; Quorum is a tool for when everything is working. Fencing is >> a tool for when things go wrong. > > I'd say: Quorum is the tool to decide who'll be alive and who's going to die, > and

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 18/04/17 08:50 PM, Dimitri Maziuk wrote: > On 04/18/2017 07:05 PM, Digimer wrote: > >> Certainly, the people creating the software have to assume that a >> split-brain is devastating. Same for people who teach others and people >> who write documentation. > > split brain is devastating when

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 04/18/2017 07:05 PM, Digimer wrote: > Certainly, the people creating the software have to assume that a > split-brain is devastating. Same for people who teach others and people > who write documentation. split brain is devastating when you're drbd. When you're a mere floating ip, assume

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 18/04/17 07:55 PM, Dimitri Maziuk wrote: > On 04/18/2017 06:15 PM, Alex Bruneau wrote: > >> Therein lies the true value: what happens when something really >> messes up? How much do you really want to drive to the DC at 3am? > > Yes, exactly: what happens when something really messes up? Will

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 04/18/2017 06:15 PM, Alex Bruneau wrote: > Therein lies the true value: what happens when something really > messes up? How much do you really want to drive to the DC at 3am? Yes, exactly: what happens when something really messes up? Will you lose a cool million bucks or will a few people

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 04/18/2017 02:47 AM, Ulrich Windl wrote: > IMHO: a valid cluster software works starting at 1 node, then per induction > also for n+1 nodes. I'm not sure what a valid fencing configuration would be in a one-node cluster, and since -- all together now -- YOU HAVE TO HAVE FENCING!.. Perhaps you

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 18/04/17 15:02, Digimer wrote: > On 18/04/17 10:00 AM, Digimer wrote: >> On 18/04/17 03:47 AM, Ulrich Windl wrote: >> Digimer schrieb am 16.04.2017 um 20:17 in Nachricht >>> <12cde13f-8bad-a2f1-6834-960ff3afc...@alteeve.ca>: On 16/04/17 01:53 PM, Eric Robinson wrote:

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 04/18/2017 02:47 AM, Ulrich Windl wrote: Digimer schrieb am 16.04.2017 um 20:17 in Nachricht > <12cde13f-8bad-a2f1-6834-960ff3afc...@alteeve.ca>: >> On 16/04/17 01:53 PM, Eric Robinson wrote: >>> I was reading in "Clusters from Scratch" where Beekhof states, "Some would

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 18/04/17 10:00 AM, Digimer wrote: > On 18/04/17 03:47 AM, Ulrich Windl wrote: > Digimer schrieb am 16.04.2017 um 20:17 in Nachricht >> <12cde13f-8bad-a2f1-6834-960ff3afc...@alteeve.ca>: >>> On 16/04/17 01:53 PM, Eric Robinson wrote: I was reading in "Clusters from

Re: [ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

On 18/04/17 03:47 AM, Ulrich Windl wrote: Digimer schrieb am 16.04.2017 um 20:17 in Nachricht > <12cde13f-8bad-a2f1-6834-960ff3afc...@alteeve.ca>: >> On 16/04/17 01:53 PM, Eric Robinson wrote: >>> I was reading in "Clusters from Scratch" where Beekhof states, "Some would >

[ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

>>> Digimer schrieb am 16.04.2017 um 20:17 in Nachricht <12cde13f-8bad-a2f1-6834-960ff3afc...@alteeve.ca>: > On 16/04/17 01:53 PM, Eric Robinson wrote: >> I was reading in "Clusters from Scratch" where Beekhof states, "Some would > argue that two-node clusters are always