The only hard-and-fast rule is that you must re-index from source when you upgrade to Solr X+2. Solr (well, Lucene) tries very hard to maintain one-major-version back-compatibility, so Solr 8 will function with Solr 7 indexes but _not_ any index _ever touched_ by 6x.
That said, it's usually a good idea to re-index anyway when jumping a major version (say Solr 7 -> Solr 8) if possible. Best, Erick On Tue, Sep 18, 2018 at 11:22 AM Christopher Schultz <ch...@christopherschultz.net> wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Walter, > > On 9/18/18 11:24, Walter Underwood wrote: > > It isn’t very clear from that page, but the two backup methods make > > a copy of the indexes in a commit-aware way. That is all. One > > method copies them to a new server, the other to files in the data > > directory. > > > > Database backups generally have a separate backup format which is > > independent of the database version. For example, mysqldump > > generates a backup as SQL statements. > > > > The Solr backup is version-locked, because it is just a copy of the > > index files. People who are used to database backups might be very > > surprised when they could not load a Solr backup into a server with > > a different version or on a different architecture. > > > > The only version-independent restore in Solr is to reload the data > > from the source repository. > > Thanks for the explanation. > > We recently re-built from source and it took about 10 minutes. If we > can get better performance for a restore starting with a "backup" > (which is likely), we'll probably go ahead and do that, with the > understanding that the ultimate fallback is reload-from-source. > > When upgrading to a new version of Solr, what are the rules for when > you have to discard your whole index and reload from source? We have > been in the 7.x line since we began development and testing and have > not had any reason to reload from source so far. (Well, except when we > had to make schema changes.) > > Thanks, > - -chris > > >> On Sep 18, 2018, at 8:15 AM, Christopher Schultz > >> <ch...@christopherschultz.net> wrote: > >> > > Walter, > > > > On 9/17/18 11:39, Walter Underwood wrote: > >>>> Do not use Solr as a database. It was never designed to be a > >>>> database. It is missing a lot of features that are normal in > >>>> databases. > >>>> > >>>> [...] * no real backups (Solr backup is a cold server, not a > >>>> dump/load) > > > > I'm just curious... if Solr has "no real backups", why is there a > > complete client API for performing backups and restores? > > > > https://lucene.apache.org/solr/guide/7_4/making-and-restoring-backups. > ht > > > > > ml > > > > Thanks, -chris > > > > > -----BEGIN PGP SIGNATURE----- > Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ > > iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAluhQlkACgkQHPApP6U8 > pFgcyRAAm4/FeeGn3eGv4CwNVfc9GrsUYc4/YexdwRT7oFUgqTC2kYeegj/YAgm3 > ZwgfLDkDL0HR51i/pp4UG8MDTB5NFtp8Jg6+JSE4SutAA72N6vnwnC1Z/T52i0xG > OqT0lFKeIL7Tt5c0FffbAMx5rgbFkzWHNWgFFqYFB0WZEzj4JM6rmAiDqLunRGPA > xAZUnZCRMXhcVZT0bmmnSGlyU+JHL0ZQrJD/WX4DOJo2ZyAvP7pSYBEU+nTfyjzJ > kE3rx1W9o269yc052FJTk5rRADuHIdirQQ/SrUN3O7Nn7Hqqi2/6sqyM34CF6wmX > IPv9frb/WTvXQ3nsFYmQVB1jEBBr5S+9pztO3jOtUbGGKCjBpVGDcOXJVBwEDzPW > yII5EjpjkoYwVB6shUI2nfaM/Y6r4aQLrZO6A5FFePhQTm6BGa/i2i1A1uLqfvHY > WMmv/QMYqXZu7hXW6l5NKpO1AtSKTZBq8iXi9BiOXSHNSxo9mT9kPLu40Uh63Gyp > EHI/SfAPWNwOj01pkbyV+siyhAWBVWpolN1SinnW3ZR16Yddd2lRmNxdfVCC32pL > OfRxrChtZ736kvm4ELzmUAUjITxpZf7AFgsrB6zyTlPRn/jvnW7sRsIsOa4BHdGC > e4oCzK7waITu6jam4Zz6e3efyxSDfT2YZ7811L098mody1n2g5k= > =PaVE > -----END PGP SIGNATURE-----
