[Zope-dev] HA storage for zope

[Wichert Akkerman]

Previously Miles Waller wrote:
> Hi,
> 
> I'm looking at a HA setup for a project, and was wondering what the current
> best way forward would be.  There seem to be a few potential options around
> for the storage end of the setup, and I'm wondering what's now considered
> the current "best practice" for this sort of setup.  Specifically, I've come
> up with three options:
> 
> 1. RelStorage
> Using this, I think I can then take care of replication/mirroring as I have
> access to a database that is already clustered in a HA environment.  My
> questions are:
>  + Are the connections opened only when zope is started?  Say I unplugged a
> network cable and then plugged it back in again (breaking the database
> connection) - will it be re-opened?
>  + How does RelStorage take care of the blob storage?
>  + Are there any details of big sites out there that use RelStorage
> (particularly on Oracle)?

The initial RelStorage development was sponsored by Jarn and Elkjøp for
exactly that purpose: Elkjøp (a chain of Scandinavian electronics
stores) uses an Oracle cluster for storage of all their Zope data.

> 2. ZeoRAID
> I could use ZeoRAID to write to maintain several independent storages
> subject to stopping the ZeoRAID server being the single point of failure (I
> posted some questions about this separately).

If I remember correctly the ZeoRAID server is stateless, so you can
use a standard redundant setup to remove the single point of failure.

> 3. ZRS
> If I'm right, ZRS still has a limitation in that there is a single server
> for writes.  Also, budget may be an issue.  Having read the factsheet, I'm a
> bit unsure as to how it is functionally different from ZeoRAID - can anyone
> explain?

>From what I hear ZRS is also fairly expensive, especially compared to
the other two options which are free.

Wichert.

-- 
Wichert Akkerman <wichert at wiggy.net>    It is simple to make things.
http://www.wiggy.net/                   It is hard to make things simple.