> it better not ever be depreciated. it has been the most reliable mechanism > for its purpose
I would like to know whether that is the consensus of Solr developers. We had been scrambling to move from Master/Slave to CDCR based on the assertion that CDCR support would last far longer than Master/Slave support. Can we now assume safely that this assertion is now completely moot? Can we now assume safely that Master/Slave is likely to be supported for the foreseeable future? Or are we forced to assume that Master/Slave support will evaporate shortly after the now-evaporated CDCR support? -----Original Message----- From: David Hastings <hastings.recurs...@gmail.com> Sent: Wednesday, September 30, 2020 3:10 PM To: solr-user@lucene.apache.org Subject: Re: Master/Slave >whether we should expect Master/Slave replication also to be deprecated it better not ever be depreciated. it has been the most reliable mechanism for its purpose, solr cloud isnt going to replace standalone, if it does, thats when I guess I stop upgrading or move to elastic On Wed, Sep 30, 2020 at 2:58 PM Oakley, Craig (NIH/NLM/NCBI) [C] <craig.oak...@nih.gov.invalid> wrote: > Based on the thread below (reading "legacy" as meaning "likely to be > deprecated in later versions"), we have been working to extract ourselves > from Master/Slave replication > > Most of our collections need to be in two data centers (a read/write copy > in one local data center: the disaster-recovery-site SolrCloud could be > read-only). We also need redundancy within each data center for when one > host or another is unavailable. We implemented this by having different > SolrClouds in the different data centers; with Master/Slave replication > pulling data from one of the read/write replicas to each of the Slave > replicas in the disaster-recovery-site read-only SolrCloud. Additionally, > for some collections, there is a desire to have local read-only replicas > remain unchanged for querying during the loading process: for these > collections, there is a local read/write loading SolrCloud, a local > read-only querying SolrCloud (normally configured for Master/Slave > replication from one of the replicas of the loader SolrCloud to both > replicas of the query SolrCloud, but with Master/Slave disabled when the > load was in progress on the loader SolrCloud, and with Master/Slave resumed > after the loaded data passes QA checks). > > Based on the thread below, we made an attempt to switch to CDCR. The main > reason for wanting to change was that CDCR was said to be the supported > mechanism, and the replacement for Master/Slave replication. > > After multiple unsuccessful attempts to get CDCR to work, we ended up with > reproducible cases of CDCR loosing data in transit. In June, I initiated a > thread in this group asking for clarification of how/whether CDCR could be > made reliable. This seemed to me to be met with deafening silence until the > announcement in July of the release of Solr8.6 and the deprecation of CDCR. > > So we are left with the question whether we should expect Master/Slave > replication also to be deprecated; and if so, with what is it expected to > be replaced (since not with CDCR)? Or is it now sufficiently safe to assume > that Master/Slave replication will continue to be supported after all > (since the assertion that it would be replaced by CDCR has been > discredited)? In either case, are there other suggested implementations of > having a read-only SolrCloud receive data from a read/write SolrCloud? > > > Thanks > > -----Original Message----- > From: Shawn Heisey <apa...@elyograg.org> > Sent: Tuesday, May 21, 2019 11:15 AM > To: solr-user@lucene.apache.org > Subject: Re: SolrCloud (7.3) and Legacy replication slaves > > On 5/21/2019 8:48 AM, Michael Tracey wrote: > > Is it possible set up an existing SolrCloud cluster as the master for > > legacy replication to a slave server or two? It looks like another > option > > is to use Uni-direction CDCR, but not sure what is the best option in > this > > case. > > You're asking for problems if you try to combine legacy replication with > SolrCloud. The two features are not guaranteed to work together. > > CDCR is your best bet. This replicates from one SolrCloud cluster to > another. > > Thanks, > Shawn >
