Removing Disks

You can remove one or more disks from MapR-FS using the disk remove command or the MapR Control System.

Warning: Removing a disk in the storage pool that contains Container ID 1 will stop your cluster. Container ID 1 contains CLDB data for the master CLDB. From the command-line, run the maprcli disk remove command without the -force 1 option first and examine the warning messages to make sure you aren't removing the disk with Container ID 1. To safely remove such a disk, perform a CLDB Failover to make one of the other CLDB nodes the primary CLDB, then remove the disk as normal.

When you remove a disk from MapR-FS, any other disks in the storage pool are also removed automatically from MapR-FS and are no longer in use (they are available but off-line). Their disk storage goes to 0%, and they are eligible to be re-added to MapR-FS to build a new storage pool. You can either replace the disk and re-add it along with the other disks that were in the storage pool, or just re-add the other disks if you do not plan to replace the disk you removed.

  • If you are removing and replacing failed disks, you can install the replacements, then re-add the replacement disks to MapR-FS, along with the other disks that were in the same storage pool(s) as the failed disks. See Handling Disk Failures for more details.
  • If you are removing disks but not replacing them, you can just re-add the other disks that were in the same storage pool(s) as the failed disks.

Before removing or replacing disks, make sure the Replication Alarm (VOLUME_ALARM_DATA_UNDER_REPLICATED) and Data Alarm (VOLUME_ALARM_DATA_UNAVAILABLE) are not raised. These alarms can indicate potential or actual data loss! If either alarm is raised, you might be able to repair the problem using the /opt/mapr/server/fsck utility before removing or replacing disks.


Using the /opt/mapr/server/fsck utility with the -r flag to repair a filesystem risks data loss. Call MapR support before using /opt/mapr/server/fsck -r.

Complete the following steps to remove disks using the MapR Control System:
  1. In the Navigation pane, expand the Cluster group and click the Nodes view.
  2. Click the name of the node from which you wish to remove disks.
  3. In the MapR-FS and Available Disks pane, select the checkboxes beside the disks you wish to remove.
  4. Click Remove Disks from MapR-FS to remove the disks from MapR-FS.
  5. Wait several minutes while the removal process completes. After you remove the disks, any other disks in the same storage pools are taken offline and marked as available (not in use by MapR).
  6. Remove the physical disks from the node or nodes according to the correct hardware procedure.