[Moosefs-users] ask about master and backup server (metalogger)

[Cuong H. B. <bhc...@gm...>]

Hi,

In the section "HOW TO PREPARE A FAIL PROOF SOLUTION WITH A REDUNDANT 
MASTER?", I'm not clear about configuration. Please tell me details.
With 2 servers A, B, I install mfsmaster on both.
- Configure A as master (CARP master), let mfsmaster running.
- Let mfsmaster stop on B. Install metalogger on B, let it running.

There are some cases as below.
1. Network connectivity on A broken, then CARP on B becomes master, but 
mfsmaster not running. How do I start it automatically in this case?

2. Network connectivity on A is okay but mfsmaster process is down. What 
should I do in this case? How do I monitor mfsmaster asynchronous so 
that I will shutdown CARP interface to switch to backup automatically?
I dont want to use cron job to poll mfsmaster process.

Please help me show some solutions for these cases.

Besides, when I read this section, I'm not clear about this paragraph
===
You also need an extra script run continuously testing the CARP 
interface state which in case if this interface goes in a MASTER mode 
would get two or three newest "changelog" files from any chunkserver 
(just by using "scp"), would also start mfsmetarestore and then 
mfsmaster. The switch time should take approximately several seconds and 
along with time necessary for reconnecting chunkservers a new master 
would be fully functional in about a minute (in both read and write modes).
===
change logs file from chunkserver? Could you tell me details for this 
paragraph with a specific example.

I'm really care about configuring master and backup failover for MooseFS.

-- 
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Regards,
Cuong Hoang Bui
ct...@ct...
bhc...@gm...
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