The only code drop was the initial branch
https://github.com/apache/solr/tree/jira/solr-17125-zero-replicas
That branch is a cleaned up version (and a better one really) of the
production code Salesforce was running back then.
Changes done since were not ported.

Any Solr node being able to get the latest copy of a shard allows no longer
opening nor discovering all cores on a node but discovering and opening
them lazily when needed (our clusters now scale to 100 000+ collections),
no longer doing shard leader elections and instead doing a best effort to
index on the same replica, limiting the number of open cores by using
transient cores in SolrCloud mode etc.

A clear benefit of such a separation of compute and storage is when there's
a high number of indexes, with only a small subset active at any given
time. This meshes well with hosting scenarios with a lot of customers but
few active at any given time.
When all indexes are active, they have to be loaded on nodes anyway.

Ilan

On Sat, Nov 29, 2025 at 12:52 AM Matt Kuiper <[email protected]> wrote:

> Thanks for your reply. What you say makes sense.
>
> Is there perhaps a fork of the Solr baseline with your changes available
> for others to use?
>
> Your solution is very compelling!
>
> Matt
>
> On Thu, Nov 27, 2025 at 3:39 AM Ilan Ginzburg <[email protected]> wrote:
>
> > I don't believe there will be future work on this topic in the context of
> > the Solr project.
> >
> > With the experience of running in production at high scale for a few
> years
> > now a modified Solr with separation of compute and storage, the changes
> (to
> > the Cloud part of Solr, but there's unfortunately no real separation
> > between single node Solr and SolrCloud code) are too big to make this
> > approach optional. Efficiently implementing such a separation requires it
> > to be the only storage/persistence layer. It changes
> > durability/availability and cluster management assumptions in fundamental
> > ways.
> >
> > Ilan
> >
> > On Fri, Nov 21, 2025 at 9:37 PM mtn search <[email protected]> wrote:
> >
> > > Hello,
> > >
> > > I am curious if there is current/future worked planned for:
> > >
> > > https://issues.apache.org/jira/browse/SOLR-17125
> > >
> > >
> > >
> >
> https://cwiki.apache.org/confluence/display/SOLR/SIP-20%3A+Separation+of+Compute+and+Storage+in+SolrCloud
> > >
> > > Thanks,
> > > Matt
> > >
> >
>

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