[HyperDB] Active Master and Passive Master with binaryreplication

[Nick White]

Jason, Andy,

Just to toss in my 2 cents,  I currently use HyperDB in nearly this same
scenario with with a multi-master setup and it is working beautifully.

My setup contains a similar configuration as to Andy's prev suggestion
of making db2 contain 'write'=>2  so it is seen basically as a fail-over
for db1.


Thanks,
Nick




On Tue, 2010-09-28 at 10:15 -0400, Andy Skelton wrote:

> Hi, Jason,
> 
> Jason Ashdown <Jason.Ashdown at futurenet.com> wrote:
> > As soon as we disable the Active Master (db1) HyperDB spits out
> errors like "No databases available with wp_4_options (global)".
> 
> This is the code that spits out that error:
> 
> if ( empty($this->hyper_servers[$dataset][$operation]) )
>   return $this->bail("No databases available with $this->table
> ($dataset)");
> 
> $operation is either "read" or "write". If you disable db1 in your
> config (I'm guessing this is what you did), you are left with db2
> which is configured for read only, not for write. If db2 is supposed
> to receive reads when db1 is disabled, your config must reflect that.
> 
> You might try configuring db2 with 'write' => 2. In case your
> configuration needs to change dynamically when the db status changes,
> you can make your configuration dynamic. One way is to have multiple
> configurations in conditional blocks.
> 
> I have not tested HyperDB with DRBD or any other multi-master setup.
> However, I did intend for HyperDB to provide the same sort of failover
> for writes that it does for reads. I'll be curious to see how you make
> it work.
> 
> Cheers,
> Andy
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