I am testing the backup/restore again but this time with the new ColumnStore image 6.2.3 - mariadb/skysql-enterprise-columnstore-handoff:sky-6.2.3-GA. At the moment I am trying to backup on sky-5.5.2-1-GA (single node) and restore on sky-6.2.3-GA (single node). I am using the columnstore-backup.sh and columnstore-restore.sh scripts. But I try to restore I am hitting a problem:

...
Warning: MariaDB versions of the current system and the backup don't match
The MariaDB version of the backup (10.5) is lower than the version of the current system (10.6).
A MariaDB upgrade will be attempted
...
ERROR 1007 (HY000) at line 810: Can't create database 'performance_schema'; database exists
FATAL ERROR: Upgrade failed

After some help from CS colleagues in this thread looks like the problem is that after the restore is started not all 7 processes are running and the mode is readonly.

I attach logs from cs 6.2.3 database. Everything was working before I try the restore. I was able to create/insert into/drop table. As you can see in the logs mcsStatus showed 7 processes the node was marked as master and readwrite. When I started the restore script it failed as before and after that only 6 processes were working - "workernode" process was missing and the mode was readonly now..