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you need a clustered file system or global filesystem
Alex
________________________________
From: lvs-users-bounces+alex.tsalik=acsacs.com@xxxxxxxxxxxxxxxxxxxxxx on behalf
of Jacob Coby
Sent: Wed 7/13/2005 10:31 AM
To: LinuxVirtualServer.org users mailing list.
Subject: Re: Distributed Filesystem
Josef Pospisil wrote:
> Dear mailinglist,
>
> i have a problem. I want to loadbalance several webservers. But there is
> also a MYSQL database. And i want to have the same content in all
> databases (for example if a user writes a news or something i want to
> have it in all databases). Of course i could use one MYSQL database for
> all webservers but i would loose the redundancy. Somebody told me i
> could do that with Distributed Filesystem. But what exactly is
> distributed filesystem and how does it work? Or is there any other way
> to keep all databases up to date?
You can't just access the same DB from all web servers? It's far easier
to add redundant web servers than redundant databases, if you care about
data integrity.
If you really need several databases, you'll have to look into
replication. MySQL has some form of it (I'm not sure of the details).
PostgreSQL has Slony. All of the big db vendors have replication.
A distributed filesystem will not help with a db.
I think there are also things that send the same UPDATE/DELETE commands
to all databases, but pulls SELECTS from whichever one is least loaded.
You are not guaranteed the data will remain in sync.
--
-Jacob
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