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From:Johan De Meersman Date:December 7 2010 1:09pm
Subject:Re: Limits to Multi-master replication?
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On Tue, Dec 7, 2010 at 11:26 AM, Matt Wallace
<lists@stripped>wrote:

> Is that a single database or a single MySQL instance?  Each domain that we
> host has it's own database (and many have more than that!), so the table
> names
> are unique to that DB/CMS install.
>

A single instance where each individual CMS has it's database. We've heavily
customized our Drupal, to make use of memcache, Squid and browser caches and
whatnot - especially logged in pages are tough. We are stuck-ish with Drupal
5, though - maybe 6 or the upcoming 7 will be better-behaved and not do
several hundred queries for a single pageview sometimes.


 We have dedicated Load Balancers to spread the traffic across multiple
> MySQL
> instances, hence the thinking behind multi-master replication - or have I
> mis-
> understood your point? :)
>

You can't really balance writes, multimaster or not. You're stuck with the
replication delay, which can leave users very confused when they just
submitted an article and it doesn't show; and even if you solve that, each
master still has to do ALL the writes anyway, so you don't really win
anything there, either.



>  Hmmm, that's an interesting concept, I'll have a think about whether
> that's a
> possible solution here as well (although I don't much fancy running 24000
> Xen
> instances!).
>

Heh, we're nowhere near there - we just provide hostings for internal
customers who prefer to have their code developed externally. Still, with a
good management setup (puppet, for instance) you could automate most, if not
all of the setup. With that volume, though, I'm sure the nice gents at
VMWare would also be very pleased to offer you lunch :-p


-- 
Bier met grenadyn
Is als mosterd by den wyn
Sy die't drinkt, is eene kwezel
Hy die't drinkt, is ras een ezel

Thread
Limits to Multi-master replication?Matt Wallace7 Dec
  • Re: Limits to Multi-master replication?Johan De Meersman7 Dec
    • Re: Limits to Multi-master replication?Matt Wallace7 Dec
      • Re: Limits to Multi-master replication?Johan De Meersman7 Dec
      • Re: Limits to Multi-master replication?Rick James8 Dec