[ZODB-Dev] Horizon for highly-available ZODB storage?

[sean.upton@uniontrib.com]

This is an interesting idea; the nice thing about a replicated block device
is that it should replicate data rather quickly, though, if I understand
correctly, the FS has to be unmounted until the backup node takes over.  Are
there any issues with corruption of a FileStorage Data.fs that have to be
dealt with as the result of an incomplete replication of data blocks via
DRBD, if for example, there is a sudden power outage on the primary node?
My main concern is the ability to have reliability without the need for
human intervention, until, perhaps after the fact - guaranteeing
site/service uptime/integrity.

Sean

-----Original Message-----
From: Fabiano Weimar dos Santos [mailto:fabiano@x3ng.com.br]
Sent: Thursday, January 03, 2002 1:33 PM
To: sean.upton@uniontrib.com; zodb-dev@zope.org
Subject: Re: [ZODB-Dev] Horizon for highly-available ZODB storage?


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Em Qui 03 Jan 2002 18:12, sean.upton@uniontrib.com escreveu:
> Happy New Year, all!
>
> I wanted to query this list to get some input on what options are likely
to
> be available for maintaining a highly-available ZEO storage server within
> the next 6-7 months.  My company has a very large, highly-demanding
project
> we are just getting started on that will heavily utilize multiple ZODB
> instances on a ZEO cluster with a 2-box ZSS strategy.  We currently do
this
> for some less-demanding projects and attain high-availability across 2
> concurrently running ZSS nodes using the Linux-HA project's Heartbeat
> clustering software; our means of replication of our FileStorage Data.fs
> from ZSS #1 to ZSS #2 is a simple daily file transfer (FTP) and restart of
> the ZSS process; 

Ok, this is fully functional but i have an alternative solution, until we 
don't have the resources for ZEO cluster replication. Do you know DRDB ??? 
You could use DRDB file system replication with journaled file systems, like

ReiserFS or Ext3. This solution, with the help of heartbeat and IPMON is a 
complete alternative for you problem. If you want to know more information 
about, please take a look at the page:

http://200.196.30.26/~sulamita.garcia/ha/links.html

There are a list of links that will help you to improve the resource of your

cluster, until a definitive ZEO solution ("the state of art").

> this is ok, since this data is updated usually just once
> daily.  But our upcoming projects will involve bigger ODBs that update far
> more often, so I wanted to get some input on what options are both
> available now, and also what new strategies will likely be available later
> in the upcoming year.

- --snip--

- -- 
Fabiano Weimar dos Santos
X3ng Web Technology
Consultoria e Desenvolvimento
Celular: 54 9114-7230
ICQ: 40187432
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