[Deploying Sakai] [sakai-nakamura] OAE Backup and Restore

[Ian Boston]

It depends if you are pre-sparse or post sparse.

If you are pre-sparse, all the data is in Jackrabbit and so you have
to use Jackrabbit backup techniques. This involves backing up the DB
and then trying to backup the local state which may be changing.
Frankly, its not easy to do Hot and most people do it Cold. We run
Jackrabbit in production to support portal state in Camtools 2008
(Sakai 2.5), which uses recursive rsyncs to get a stable state of the
local file system. Its worked for about 4 years now, but its quite
scary and we have only had to do one recover, which IIRC was
successful.

If you are running pre-sparse in a cluster without buying a custom
persistence manager form Day (Adobe), if they will sell it to you...
then you will notice that the performance of the cluster is inversely
proportional to the number of nodes in the cluster. Which is one of
the reasons why I tried so hard to get the project to dedicate time to
writing a new content system, eventually giving up and doing it in my
own time. (bitter that I was forced to do that?, yes!, glad I did?,
absolutely, :) ).
In addition to the performance issue, most notable with updates, you
have to watch the centralised Journal table which is the
sychronization point over all nodes in the cluster (hence the perfect
parallel slowdown), and ensure that when you use a backup, you replay
that journal from the transaction the backup was created. Its vital to
get the local state in sync with the journal otherwise the Lucene
index inside Jackrabbit becomes out of sync.

-------------------------------------------------------------------------

If you are on sparse then all your user content is in a DB and the
blobs are on filesystem, immutable. You can then do a normal backup as
you do with Sakai CLE. You should run Jackrabbit on a local Derby
instance and not back it up, since it should only ever be a reflection
of the contents of the bootstrap Jar.

The search index needs a bit more care, but its OOTB Solr so whatever
technique works for you with Solr is good. AFAIK No one is running in
a cluster with Solr yet and I believe there are some issues which I am
trying to address at Cambridge. We will be running multi master for
PostgreSQL and elected Master/Slave with replication for Solr to
enable us to a) Scale elastically and b) do real time backup via
replication.



This message may bounce from production due to one of the lists not
recognizing my subscription there.

HTH
Ian

On 6 July 2011 17:33, Clay Fenlason <clay.fenlason at et.gatech.edu> wrote:
> I don't want to interrupt, but am copying the production list. It
> seems the best channel for capturing discussion for production issues
> as the OAE goes into wider use.
>
> ~Clay
>
> ---------- Forwarded message ----------
> From: Ray Davis <ray at media.berkeley.edu>
> Date: Wed, Jul 6, 2011 at 12:26 PM
> Subject: [sakai-nakamura] OAE Backup and Restore
> To: sakai-kernel <sakai-kernel at googlegroups.com>
>
>
> How are NYU, CSU, Cambridge, and other OAE pilot schools planning to
> back up and restore the application (particularly on a cluster)?
>
> I'm not finding any information post-Sparse, although there were some
> useful notes on Jackrabbit-based Sakai 3 backups at
>
> http://groups.google.com/group/sakai-kernel/browse_thread/thread/bb58712ba4260982/
> and
> https://confluence.sakaiproject.org/display/KERNDOC/Your+Last+Day+with+Sakai+Nakamura...
>
> Looks like most of this should still apply but I might be missing
> something important.
>
> Thanks,
> Ray
>
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