[Kamailio-Users] Redundancy and fault-tolerance

[Iñaki Baz Castillo]

2009/3/3 Henning Westerholt <henning.westerholt at 1und1.de>:
>> Simpler than that. Forget DB replication stuff. I just mean that if
>> you have a MySQL 1 with a large MyISAM table and you copy it to other
>> server using "scp/rsync", you will get a non optimized or corrupted
>> table (even if both servers have same CPU, architecture and file
>> system).
>>
>> I've experimented it by copying with "rsync" a 2 GB long MyISAM table.
>> After restarting the MySQL-2 and run a SQL command to check tables
>> [1], you probably will get a "NOT OPTIMIZED TABLE" and you must to
>> repair it. This is the best case.

I would like to add that the "scp" copy was performed after stoping
MySQL 1, if not, be sure that you can get a *corrupted* table (more
dangerous when using InnoDB).
But anyway, being MysQL 1 stoped I got a "non optimized" table after
copying it to other server using "scp".


>> PD: This is based on my experience with MySQL. However I'have no too
>> much knowledge on it.
>
> Hi Iñaki,
>
> ok, thanks for the clarification. This sounds strange. I mean, how is this
> different to a normal backup/ restore cycle when some machine crash? I'd
> expect that it simply continue to use the restored data.

I don't know. Perhaps MyISAM format relies on file system nodes, so
doing a "cp" or "scp" is not secure (or maybe it's secure but you must
repair the table after it).



-- 
Iñaki Baz Castillo
<ibc at aliax.net>