We are overlaping mails :P

What I don't understand is the need of a shared storage in this case. It would 
be a lot better to have the data folder inside each server virtual disk to 
avoid troubles with the shared storage; I really see no reason for such 
configuration here.

Now, getting into the solution rather than in the problem. I suggest you to do 
the following:

1. First of all, backup your data folder for both nodes. Just in case. Make 
backup with postgres stopped to avoid problems.
2. Choose one node which will be considered up-to-date(Let's say "Node A")
3. Dump your database(s) on that node, excluding the bdr schema on each db. 
Dump also your globals
4. Wipe or rename your data folder on each node, and then initialize each node. 
Do not configure BDR yet.
5. Restore your data(backed up at step 3) on Node A
6. Configure BDR on Node A
7. Add Node B to the replication group, using "bdr_init_copy" to make it 
replicate from Node A.

That should do the trick. There is another possibility: Drop the replication 
configuration no Node A, and then start from scratch(Steps 1, 6 & 7). However, 
this can be troublesome, as it involves editing bdr & postgres schemas, and 
that can lead you to problems on the future, so I'd recommend you the "long" 
way.

Feel free to ask any question regarding this issue. Looks serious....

Alvaro Aguayo
Jefe de Operaciones
Open Comb Systems E.I.R.L.

Oficina: (+51-1) 3377813 | RPM: #034252 / (+51) 995540103  | RPC: (+51) 
954183248
Website: www.ocs.pe

----- Original Message -----
From: "Slava Bendersky" <volga...@skillsearch.ca>
To: "Alvaro Aguayo Garcia-Rada" <aagu...@opensysperu.com>
Cc: "pgsql-general" <pgsql-general@postgresql.org>, "John R Pierce" 
<pie...@hogranch.com>
Sent: Thursday, 31 March, 2016 12:28:09 AM
Subject: Re: [GENERAL] bdr replication



Hello Alvaro, 
We running BDR where each PostgreSQL vm is a master and shared storage only on 
hypervisor level. All vm leave with own virtual disk. Right now we have 2 
server for redundancy which have shared network between them. Issue that BDR is 
working right now see log below. And my question how to restore BDR replication 
correctly. 


volga629 

----- Original Message -----

From: "Alvaro Aguayo Garcia-Rada" <aagu...@opensysperu.com> 
To: "volga629" <volga...@skillsearch.ca> 
Cc: "pgsql-general" <pgsql-general@postgresql.org>, "John R Pierce" 
<pie...@hogranch.com> 
Sent: Thursday, 31 March, 2016 02:19:42 
Subject: Re: [GENERAL] bdr replication 


What's the purpose of such configuration? Doesn't makes sense for me. The only 
reasonable case where you would want to put the data folder on a shared storage 
is for usage with warm standby, where you can have a secondary server which 
serves as a read-only replica, and can be rpomoted to master on master failure. 

If you intend high availability, you'd rather try it at VM level, like vmware 
HA or Proxmox HA. That will make your VM run on any hypervisor in the group 
disregarding the failure of some node. 

Regards, 

Alvaro Aguayo 
Jefe de Operaciones 
Open Comb Systems E.I.R.L. 

Oficina: (+51-1) 3377813 | RPM: #034252 / (+51) 995540103 | RPC: (+51) 
954183248 
Website: www.ocs.pe 

----- Original Message ----- 
From: "Slava Bendersky" <volga...@skillsearch.ca> 
To: "John R Pierce" <pie...@hogranch.com> 
Cc: "pgsql-general" <pgsql-general@postgresql.org> 
Sent: Wednesday, 30 March, 2016 10:57:13 PM 
Subject: Re: [GENERAL] bdr replication 



In my case only virtual hosts are use share storage (feed from glusterfs), but 
actual virtual machines have own separate disks and all PostgreSQL run on 
separate data directories. 


volga629 

----- Original Message ----- 

From: "John R Pierce" <pie...@hogranch.com> 
To: "pgsql-general" <pgsql-general@postgresql.org> 
Sent: Thursday, 31 March, 2016 00:34:55 
Subject: Re: [GENERAL] bdr replication 


On 3/30/2016 8:09 PM, Slava Bendersky wrote: 
> Is any share storage technology recommended for PostgreSQL in virtual 
> environment ? 
> Ok what I will do is going take backups, shutdown both virtual servers 
> and place all vm use local disk on server only. 


'share storage technology'... um. thats such a vague term, it can 
mean lots of things. 

each postgres instance needs its own data store, two instances can NOT 
share the same files under any condition. these data stores can be 
on SAN or NAS, as long the storage is reliable about committed random 
writes, and as long as two different servers aren't using the SAME 
directory for their data stores. 

-- 
john r pierce, recycling bits in santa cruz 



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