Let me qualify this by saying this question relates to future planning purposes only. We recently upgraded our DEV and DEV DR clusters from 7.0.14 to 7.1.4. I noticed in there are now two versions listed in our software directory:
15:57:09 [memsql-admin@CH-D-MEM-AGGR1 ~/scripts][Dev]$ cd /opt
15:57:14 [memsql-admin@CH-D-MEM-AGGR1 /opt][Dev]$ ls -l
total 8
drwxr-xr-x. 5 root root 121 Jul 17 2019 chef
drwxr-xr-x 15 root root 4096 Mar 28 16:41 memsql-server-7.0.14-e9a36d3e69
drwxr-xr-x 16 root root 4096 Jul 14 19:02 memsql-server-7.1.4-516dfe4088
My question is, in the event that we would need to rollback to the previous version, what would the path be given that we do currently take nightly incremental backups of all our databases in the cluster and a full prior to the upgrade?
Unfortunately at this time MemSQL does not support downgrading directly. So given the fact you have a pre-upgrade backup, if you wanted to rollback to an earlier version of the engine you would roughly follow these steps:
take a backup of your cluster configuration using memsql-deploy generate-cluster-file
delete all the nodes in your cluster
rollback to an earlier version of the engine via memsql-deploy uninstall (to remove the version you don’t want)
re-create your cluster using memsql-deploy setup-cluster
restore from backup
Note that a backup taken with MemSQL engine version X can only be restored to MemSQL engine version X and above.