(Simple?) High availability question

[Madison Kelly]

Ian Petersen wrote:
> On 6/1/07, Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
>> I believe mysql has a replicating
>> server backend, although apparently that backend is much slower and has
>> less features than the regular one, so it is a major tradeoff there.
> 
> I used to work for a place that relied on MySQL for the majority of
> its database needs.  I believe the MySQL dbs were all replicating in
> multi-master mode.  It was apparently adequate for their needs, but I
> don't know what happens if/when one of the db machines fails.  I've
> heard that multi-master database replication is a thorny problem from
> a theoretical perspective (I think it was Seneca and Christopher
> Browne I overheard at a LUG meeting).  I also remember that the tech
> support guru occasionally had to issue strange commands to get things
> unwedged that included a memorized magic byte offset into MySQL's
> binary logs.  On the other hand, this company had 24x7 uptime
> obligations to its customers and unscheduled downtime had direct
> consequences on their bottom line, so the replication must have been
> doing something worthwhile.
> 
> I prefer PostgreSQL for my own database needs, but I think it's
> because I was exposed to PostgreSQL before MySQL, and, at the time,
> MySQL's position on ACID was reprehensible.  I hear that MySQL 5 is
> much better ACID-wise, and it's had replication for a long time.  It
> might be worth looking into.
> 
> Ian

Well, I use roundcube webmail with MySQL holding it's data (couldn't get 
it working on PgSQL). Otherwise I wouldn't have to worry about MySQL at 
all. In this case though, I do, so thank you for the info. I hadn't 
asked about MySQL yet because I was trying to keep my poor noggin' 
focused on as few crazy things as possible. In our case though, 
switching to MySQL is both not appealing and not practical. It's nice to 
know it'll work for the few instances we need it though!

Madi


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