Beware the SST
In Percona XtraDB Cluster (PXC) I often run across users who are fearful of SSTs on their clusters. I’ve always maintained that if you can’t cope with a SST, PXC may not be right for you, but that doesn’t change the fact that SSTs with multiple Terabytes of data can be quite costly.
SST, by current definition, is a full backup of a Donor to Joiner. The most popular method is Percona XtraBackup, so we’re talking about a donor node that must:
- Run a full XtraBackup that reads its entire datadir
- Keep up with Galera replication to it as much as possible (though laggy donors don’t send flow control)
- Possibly still be serving application traffic if you don’t remove Donors from rotation. …