Actually there are situation where a restore is needed, suppose that someone
does some error and deletes all documents from a collection, or maybe deletes a
series of document, etc. I know that this is not likely to happen, but in
mission critical enterprise system, we always need a detailed procedure for
disaster recovering.
For such scenario we need to plan the worst case, where everything is lost.
With Master Slave is just a matter of recreating machines, reconfigure the
core, and restore a backup, and the game is done, with SolrCloud is not really
clear for me how can I backup / restore data. From what I've found in the
internet I need to backup every shard of the collection, and, if we need to
restore everything from a backup, we can recreate the collection and then
restore all the individual shards. I do not know if this is a supported
scenario / procedure, but theoretically it could work.
--
Gian Maria Ricci
Cell: +39 320 0136949
-----Original Message-----
From: Alessandro Benedetti [mailto:abenede...@apache.org]
Sent: giovedì 14 gennaio 2016 10:46
To: solr-user@lucene.apache.org
Subject: Re: Pro and cons of using Solr Cloud vs standard Master Slave Replica
It's true that SolrCloud is adding some complexity.
But few observations :
SolrCloud has some disadvantages and c
an't beat the easiness and simpleness
> of
> Master Slave Replica. So I can only encourage to keep Master Slave
> Replica in future versions.
I agree, it can happen situations when you have really simple and not critical
systems.
Anyway old style replication is still used in SolrCloud, so I think it is going
to stay for a while ( until is replaced with something else) .
To answer to Gian :
One of the problem I've found is that I've not found a simple way to backup
> the content of a collection to restore in situation of disaster recovery.
> With simple master / slave scenario we can use the replication handler
> to generate backups that can be easily used to restore content of a
> core, while with SolrCloud is not clear how can we obtain a full
> backup
To be fair, Disaster recovery is when SolrCloud shines.
If you lose random nodes across your collection, you simply need to fix them
and spin up again .
The system will automatically restore the content to the last version availa
ble ( the tlog first and the leader ( if the tlog is not enough) will help the
dead node to catch up .
If you lose all the replicas for a shard and you lose the content in disk of
all this replicas ( index and tlog), SolrCloud can't help you.
For this unlikely scenarios a backup is suggested.
You could restore anyway the backup only to one node, and the replicas are
going to catch up .
Probably is just a matter of backupping every shard with standard
> replication handler and then restore each shard after recreating the
> collection
Definitely not, SolrCloud is there to avoid this manual stuff.
Cheers
On 14 January 2016 at 08:58, Gian Maria Ricci - aka Alkampfer <
alkamp...@nablasoft.com> wrote:
> I agree that SolrCloud has not only advantages, I really understand
> that it offers many more features, but it introduces some complexity.
>
> One of the problem I've found is that I've not found a simple way to
> backup the content of a collection to restore in situation of disaste
r
> recovery. With simple master / slave scenario we can use the
> replication handler to generate backups that can be easily used to
> restore content of a core, while with SolrCloud is not clear how can we
> obtain a full backup.
> Probably is just a matter of backupping every shard with standard
> replication handler and then restore each shard after recreating the
> collection, but I've not found (probably I need to search better)
> official documentation on backup / restore procedures for SolrCloud.
>
> Thanks.
>
> --
> Gian Maria Ricci
> Cell: +39 320 0136949
>
>
> -----Original Message-----
> From: Bernd Fehling [mailto:bernd.fehl...@uni-bielefeld.de]
> Sent: giovedì 14 gennaio 2016 08:22
> To: solr-user@lucene.apache.org
> Subject: Re: Pro and cons of using Solr Cloud vs standard Master Slave
> Replica
>
> SolrCloud has some disadvantages and can't beat the easiness and
> simpleness of Master Slave Replica. So I can only encourage to keep
> Master Slave Replica in
future versions.
>
> Bernd
>
> Am 13.01.2016 um 21:57 schrieb Jack Krupansky:
> > The "Legacy Scaling and Distribution" section of the Solr Reference
> > Guide also gives info elated to so-called master-slave mode:
> > https://cwiki.apache.org/confluence/display/solr/Legacy+Scaling+and+
> > Di
> > stribution
> >
> > Also, although the old master-slave mode is still technically
> > supported in the sense that the code and doc is still there, You
> > won't be able to get the level of community support here on the
> > mailing list as you can get for SolrCloud.
> >
> > Unless you're simply trying to decide whether to leave an old legacy
> > system as-is with the old distributed mode, nobody should be
> > considered a fresh new distributed Solr deployment with anything
> > other
> than SolrCloud.
> >
> > (Hmmm... have any of the committers considered deprecating the old
> > non-SolrCloud distributed mode features?)
>
> -1
>
> >
> > -- Jack Krupansky
> >
> > On Wed, Jan 13, 2016 at 9:02 AM, Shiv
aji Dutta
> > <sdu...@hortonworks.com>
> > wrote:
> >
> >> - SolrCloud uses zookeeper to manage HA
> >> - Zookeeper is a standard for all HA in Apache Hadoop
> >> - You have collections which will manage your shards across nodes
> >> - SolrJ Client is now fault tolerant with CloudSolrClient
> >>
> >> This is the way future direction of the product will go.
> >>
> >>
> >>
> >> On 1/13/16, 5:58 AM, "Gian Maria Ricci - aka Alkampfer"
> >> <alkamp...@nablasoft.com> wrote:
> >>
> >>> Thanks.
> >>>
> >>> --
> >>> Gian Maria Ricci
> >>> Cell: +39 320 0136949
> >>>
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: Shawn Heisey [mailto:apa...@elyograg.org]
> >>> Sent: lunedì 11 gennaio 2016 18:28
> >>> To: solr-user@lucene.apache.org
> >>> Subject: Re: Pro and cons of using Solr Cloud vs standard Master
> >>> Slave Replica
> >>>
> >>> On 1/11/2016 4:28 AM, Gian Maria Ricci - aka Alkampfer wrote:
> >>>> a customer need a comprehensive list of all pro and cons of using
> >>>> standard Master Slave replica VS using Solr Cloud. I¹m interested
> >>>> especially in query performance consideration, because in this
> >>>> specific situation the rate of new documents is really slow, but
> >>>> the amount of data is about 50 millions of document, and the
> >>>> index size on disk for single core is about 30 GB.
> >>>
> >>> The primary advantage to SolrCloud is that SolrCloud handles most
> >>> of the administrative and operational details for you automatically.
> >>>
> >>> SolrCloud is a little more complicated to set up initially,
> >>> because you must worry about Zookeeper as well as Solr, but once
> >>> it's properly set up, there is no single point of failure.
> >>>
> >>>> Such amount of data should be easily handled by a Master Slave
> >>>> replica with a single core replicated on a certain number of
> >>>> slaves, but we need to evaluate also the option of SolrCloud,
> >>>> especially for fault tolerance.
> >>>>
> >>>
> >>> Once you're beyond in
itial setup, fault tolerance with SolrCloud is
> >>> much easier than master/slave replication. Switching a slave to a
> >>> master is possible, but the procedure is somewhat complicated.
> >>> SolrCloud does not
> >>> *have* masters, it is a true cluster.
> >>>
> >>> With master/slave replication, the master handles all indexing,
> >>> and the finished index segments are copied to the slaves via HTTP,
> >>> and the slaves simply need to open them. SolrCloud does indexing
> >>> on all shard replicas, nearly simultaneously. Usually this is an
> >>> advantage, not a disadvantage, but in heavy indexing situations
> >>> master/slave replication
> >>> *might* show better performance on the slaves.
> >>>
> >>> Thanks,
> >>> Shawn
> >>>
> >>>
> >>
> >>
> >
>
>
--
--------------------------
Benedetti Alessandro
Visiting card : http://about.me/alessandro_benedetti
"Tyger, tyger burning bright
In the forests of the night,
What immortal hand or eye
Could frame thy fearful symm
etry?"
William Blake - Songs of Experience -1794 England
