The issue linked by Erick is really interesting. Gia, to answer to your further question :
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. So we are in the worst case, you lost everything. But you were doing the backup for each shard periodically. You create again the collection, and you restore the backup on each leader. Then all the replicas are going to catch up automatically. And old style replication will happen under the hood. I don't see this as an additional disadvantage of SolrCloud , I think we are still talking about the "disadvantage" of a longer and more complicated initial setup. With the issue Erick mentioned we are going to be potentially able to make that part as easy as possible. Cheers On 14 January 2016 at 14:19, Gian Maria Ricci - aka Alkampfer < alkamp...@nablasoft.com> wrote: > 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 > -- -------------------------- 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 symmetry?" William Blake - Songs of Experience -1794 England
