Answers: <p>Gluster has built in data "translators" that automatically replicate data across all of your bricks. The particular type of translator you're interested in is called AFR for automatic file replication. The AFR translator also uses the DHT (distributed hash table) translator. It's important that you have at least two master bricks since if you only have one, you have a single point of failure. As long as you have at least two bricks, an auto-healing process is triggered by GlusterFS's daemon (it's automatically installed when you invoke <code>gluster</code> the first time) using the other master server's replicated/translated data if anything goes wrong. Actual disaster recovery that the auto healing can't fix requires going through a <a href="http://blog.gluster.org/author/awfrazer/" rel="nofollow noreferrer">careful process documented here.</a></p>
  
  <p>Other wisdom on the topic (for example, <a href="https://access.redhat.com/documentation/en-US/Red_Hat_Storage/3.1/html/Administration_Guide/chap-Recommended-Configuration_Dispersed.html" rel="nofollow noreferrer">Redhat's documentation</a>) recommends having at least six bricks in two sets, actually. This way, "even if we lose two bricks from each set, there is no data loss". Basically, the more bricks you have, the more redundancy you have, and the less chance of data loss you have (however, it'll become cost-prohibitive and time-prohibitive after a while).</p>
  
Answers: CC BY-SA 3.0
Answers: 2017-03-01T22:03:28.920Z
Answers: 2017-03-01T22:03:28.920Z
Answers: Peter G
Answers: <p>Usually you have at least two replicas of data between the nodes of GlusteFS cluster. </p>
  
  <p>If you need details about handover between the nodes (in case of one node fail) you can check <a href="https://unix.stackexchange.com/questions/213705/glusterfs-how-to-failover-smartly-if-a-mounted-server-is-failed">this</a> answer in Unix and Linux SE site</p>
  
Answers: CC BY-SA 3.0
Answers: 2017-03-01T16:25:39.503Z
Answers: 2017-03-01T16:25:39.503Z
Answers: 2017-04-13T12:37:20.510Z
Answers: Romeo Ninov
Body: <p>What happens when one of the storage bricks goes down (HDD failure), how does GlusterFS deal with data recover? Is the stored data still safe?</p>
  
Tags: <storage><glusterfs>
Title: How efficiently does GlusterFS deal with failures?
UserDisplayName: kenorb
ThreadText: # How efficiently does GlusterFS deal with failures?
  
  (Asked by: username_0 on 2017-03-01)
  
  What happens when one of the storage bricks goes down (HDD failure), how does GlusterFS deal with data recover? Is the stored data still safe?
  
  **Tags:** storage, glusterfs
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2017-03-01. Score: 4 | Accepted answer
  
  Gluster has built in data "translators" that automatically replicate data across all of your bricks. The particular type of translator you're interested in is called AFR for automatic file replication. The AFR translator also uses the DHT (distributed hash table) translator. It's important that you have at least two master bricks since if you only have one, you have a single point of failure. As long as you have at least two bricks, an auto-healing process is triggered by GlusterFS's daemon (it's automatically installed when you invoke `gluster` the first time) using the other master server's replicated/translated data if anything goes wrong. Actual disaster recovery that the auto healing can't fix requires going through a [careful process documented here.](http://blog.gluster.org/author/awfrazer/)
  
  Other wisdom on the topic (for example, [Redhat's documentation](https://access.redhat.com/documentation/en-US/Red_Hat_Storage/3.1/html/Administration_Guide/chap-Recommended-Configuration_Dispersed.html)) recommends having at least six bricks in two sets, actually. This way, "even if we lose two bricks from each set, there is no data loss". Basically, the more bricks you have, the more redundancy you have, and the less chance of data loss you have (however, it'll become cost-prohibitive and time-prohibitive after a while).
  
  
  ---
  
  ### Answer by username_2 on 2017-03-01. Score: 2
  
  Usually you have at least two replicas of data between the nodes of GlusteFS cluster.
  
  If you need details about handover between the nodes (in case of one node fail) you can check [this](https://unix.stackexchange.com/questions/213705/glusterfs-how-to-failover-smartly-if-a-mounted-server-is-failed) answer in Unix and Linux SE site
  
  
  ---
  
  