CODEWITHSUNDEEP
cassandracassandra-3.0
namitya
namitya

Reputation: 1

Cassandra back up and recovery - drop table / schema alter

I am working on a cassandra backup and recovery strategy for our cassandra system and am trying to understand how the backup and sstable recovery works in cassandra. Here are of my observations and related questions (my need is to setup a standby/backup cluster which would become active if the primary cluster goes down.. so I want to keep them in sync in terms of data, so I want to take periodic backups at my active cluster and recover to the standby cluster)

  1. Took a snapshot backup. Dropped a table in cassandra. Stopped cassandra, recovered from the snapshot backup (copied the sstables to the data/ folder), started cassandra. Ran cqlsh on the node, and I still do not see the table created. Should this work? Am I missing any step ?
  2. In the above scenario, I then tried to re-setup the schema (I take backup of the schema in the snapshot) using the cql commant source . This created the table for me. However it creates a "new version" of table for me. When I recover the snapshot has the older version (different uuid labelled folders for table). After recovery, I still see no data in the table. Possibly because I created a new table?

I was finally able to recover data after running nodetool repair and using sstableloader to restore table data from another node in the cluster. My question is
a. what is the right way to setup a new (blank- no schema) cluster from a snapshot? How do you setup the schema and recover data?

b. how do you restore a cluster from a backup with table alterations. How do you bring a cluster running an older version of schema to a newer version of schema when recovering from a backup (snapshot or incremental)?

(NOTE: cassandra newbie here)

Upvotes: 0

Views: 485

Answers (1)

Jim Wartnick
Jim Wartnick

Reputation: 2196

So if you want to restore a snapshot, you need to copy the snapshot files back to the sstable directory and then run: nodetool refresh. You can read: https://docs.datastax.com/en/dse/5.1/dse-admin/datastax_enterprise/operations/opsBackupSnapshotRestore.html

for more information. Also, there are 3rd party tools that can back up your data and then restore it as it was at the time of the backup. We use a tool: Cohesity (formally Talena/Imanis). It has a lot of capabilities (refreshing A to B, restore/rename, etc.). There are other popular ones as well. All of them have costs associated with them.

Hopefully that helps?

-Jim

Upvotes: 0

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