Community

MarkLogic 10 and Data Hub 5.0

Latest MarkLogic releases provide a smarter, simpler, and more secure way to integrate data.

Read Blog →

Company

Stay On Top Of Everything MarkLogic

Be the first to know! News, product information, and events delivered straight to your inbox.

Sign Me Up →

 
Knowledgebase:
MarkLogic Fundamentals FAQ - Database Replication/Disaster Recovery
23 November 2021 06:22 PM

Question Answer Further reading
How many replicas (Database Replication) should each of my primary databases have?
  • One replica per each primary database
  • Multiple replicas are not typically worth the additional administrative complexity or resource provisioning

KB Articles:

Do my primary and replica clusters have to be the same spec?
  • Slow replicas will throttle the performance of your primary cluster.
  • Therefore, your replica should be provisioned to avoid primary throttling - which typically means a similar hardware specification

 KB Articles:

Documentation:

What do I do about a lagging primary?

You can either:

  • Speed up the replica by reducing traffic to the replica, or adding hardware resources to the replica - or both
  • Pause replication - be aware you'll no longer have a synchronized DR copy until replication is re-enabled

KB Articles:

Documentation:

In terms of disaster recovery (DR) - how do I choose between backup/recovery or replication?
  • Database Replication
    • Best if you need a more synchronized copy of your data
    • Needs a bigger hardware footprint
    • Can result in primary throttling if under-provisioned or under heavy load
  • Backup/Restore
    • Best if you are not sufficiently provisioned for a more synchronized DR copy, as seen with database replication
    • Results in a more unsynchronized snapshot copy of your data

KB Articles:

Documentation:

Can I do multi-primary replication i.e., have primary databases on both the clusters on a pair of coupled clusters?
  • Database replication is intended for disaster recovery (DR) & redundancy
  • For DR purposes, the recommended configuration is a dedicated primary cluster for all primary databases and a dedicated DR cluster for all replicas of those primary databases
  • Because of administrative complexity and compromised DR functionality, multi-primary DR configurations are not recommended

Documentation:

Should I replicate the auxillary databases?
  • Always replicate your Security database when setting up Database replication

  • Separate security databases on both primary and replica clusters are not recommended due to administrative complexity

  • Avoid replicating the App-Services database

Documentation:

Can my primary and replica both write to the same shared storage?

Avoid writing both primary and replica to the same shared storage since it results in a single-point failure architecture, thereby defeating the purpose of DR

KB Articles:

How many bootstrap hosts should my cluster have?

Only mark the hosts that hold your security forests (and its local disk failover copy) as bootstrap hosts to avoid too many unnecessary connections between primary & replica clusters.

Documentation

How do I upgrade replicated environments?

Replica First. If Security DB is replicated then Replica cluster must be upgraded before Master.

Documentation

How do I divert traffic away from my primary to replica cluster?
  • Disable database replication for the database on the replica cluster.
  • Make the replica cluster/database as the master.
  • Rolling Back to the Non-Blocking Timestamp on the new master

Documentation

(2 vote(s))
Helpful
Not helpful

Comments (0)