Disk Issues Troubleshooting Hub

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4 min read

(For Nodes in a MapR Cluster)

Disk-related issues are one of the more common ones faced by MapR customers. These issues come up mainly while adding or removing a disk or when there is a disk failure.When adding a disk, we need to make sure the disk is not part of LVM and that no other process is using the disk. We also need to make sure the disk has proper permissions and is not formatted to any partitions.Disk failure happens for various reasons, such as:

  • I/O error;
  • Disk disappears from OS; or
  • Bad block in disk. I/O error can happen due to issues in the underlying hardware or network or due to heavy processing in disks.

Troubleshooting Common Disk Issues

Article Number Article Title Article Description
000002988 How to recover from disk failures caused by slow MapR XD/MFS disks Intended for general troubleshooting of disk failures caused by I/O errors, slow disks, EIO errors, etc.
000003064 Storage pool on the cluster node fails due to CRC check To perform cyclic redundancy check on a storage pool when storage pool becomes offline due to a bad block
000003409 How to fix disk failure with error missing disk When disk from OS is removed or renamed
000003435 Disk is failing with error "No such device" When disk from OS is removed or renamed or references of disk path are not found in /proc/partitions file
Disk Configuration (Addition/Removal)
000002813 Unable to re-add a MapR XD disk to a node after disk replacement This article describes an issue when disk addition after replacing a failed disk can fail with an EBUSY or 'Device or Resource Busy' errors
000002728 How to resolve having a disparate number of disks in the storage pools on a node MFS does not allow adding a disk to an existing storage pool. Sometimes the user creates multiple storage pools with varying number of disks per storage pool. This article describes how to rectify such a situation.
000002822 Best practices when adding disks to MapR XD Focuses on how to avoid common mistakes while doing disk addition
000003449 Disk setup error: "Error 13, Permission denied. Disk load /dev/mapper/luks-sdd" for LUKS setup Use if you see "permission denied" errors while doing LUKS setup.
Other Common Issues
000002968 False NODE_ALARM_DISK_FAILURE alarm coming on multi-mfs This issue happens in 5.2.2, when even though all the SPs and disks are online, MapR cluster still shows a false disk failure alarm.

About the Articles

To the committed MapR Support team, Knowledge Articles are a byproduct of solving real customer issues. Given the complexity of technical challenges in this area and given that users have a wide latitude of configurability in their setups, the focus of these articles is to enhance user education on self-solving technical issues. Note that the guidance on what log files are applicable for what issue-types is of high value here. This attempt is to cover the most common issues; it is not an exhaustive compilation. These tips and tricks have been verified to be helpful for several customer cases before being published to the Support Portal.

  1. Disk Balancing Articles: https://mapr.com/support/s/topic/0TO0L000004agNtWAI/diskbalancing
  2. MapR CLDB Articles: https://mapr.com/support/s/topic/0TO0L000004agNZWAY/mapr-cldb
  3. Support Portal Known Issues: https://mapr.com/support/s/knownissues
  4. Support Advisories: https://mapr.com/support/s/SupportAdvisories

This blog post was published May 03, 2018.