recover-disk draft

docs/content/latest/troubleshoot/nodes/_index.md

@@ -49,4 +49,15 @@ menu:
       </div>
     </a>
   </div>
+  <div class="col-12 col-md-6 col-lg-12 col-xl-6">
+    <a class="section-link glyphicon-floppy-disk" href="check-stats">
+      <div class="head">
+        <img class="icon" src="/images/section_icons/troubleshoot/troubleshoot.png" aria-hidden="true" />
+        <div class="title">Disk failure</div>
+      </div>
+      <div class="body">
+        How to recover a YB-TServer from disk failure
+      </div>
+    </a>
+  </div>
 </div>

docs/content/latest/troubleshoot/nodes/recover-disk.md

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+---
+title: Disk failure
+linkTitle: Disk failure
+description: Recover failing disk
+aliases:
+  - /troubleshoot/nodes/disk-failure/
+menu:
+  latest:
+    parent: troubleshoot-nodes
+    weight: 849
+isTocNested: true
+showAsideToc: true
+---
+
+YugabyteDB can be configured to use multiple storage disks by setting the [`--fs_data_dirs`](../../reference/configuration/yb-tserver.md) configuration option.
+This introduces the possibility of disk failure and recovery issues.
+
+## Cluster replication recovery
+The `yb-tserver` service automatically detects disk failures and attempts to spread the data from the failed disk to other healthy nodes in the cluster.
+In a single-zone setup with a replication factor (RF) of `3`: if you started with four nodes or more, 
+then there would be at least three nodes left after one failed. 
+In this case, rereplication is automatically started if a YB-TServer or disk is down for 10 minutes.
+
+In a multi-zone setup with a replication factor (RF) of `3`: YugabyteDB will try to keep one copy of data per zone. 
+In this case, for automatic rereplication of data, a zone needs to have at least two YB-TServers so that if one fails, 
+its data can be rereplicated to the other. Thus, this would mean at least a six-node cluster.
+
+## Failed disk replacement
+The steps to replace a failed disk are:
+
+1. Stop the YB-TServer node.
+2. Replace the disks that have failed.
+3. Restart the `yb-tserver` service.
+
+On restart, the YB-TServer will see the new empty disk and start replicating tablets from other nodes.