Disabling PDL AutoRemove feature vSphere 6.x/7.x
Article ID: 310084
Updated On:
Products
VMware vSphere ESXi
Issue/Introduction
This article provides information on the Permanent Device Loss (PDL) AutoRemove feature. This is enabled by default in all supported ESXi versions.
For more information regarding Permanent Device Loss (PDL) and how this differs from All-Paths-Down, see Permanent Device Loss (PDL) and All-Paths-Down (APD) in vSphere 6.x and 7.x (2004684).
For more information regarding Permanent Device Loss (PDL) and how this differs from All-Paths-Down, see Permanent Device Loss (PDL) and All-Paths-Down (APD) in vSphere 6.x and 7.x (2004684).
Environment
VMware vSphere ESXi 6.7
VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.5
VMware vSphere ESXi 6.0
VMware vSphere ESXi 7.0.0
VMware vSphere ESXi 5.5
VMware vSphere ESXi 6.5
VMware vSphere ESXi 6.0
VMware vSphere ESXi 7.0.0
Resolution
Permanent Device Lost (PDL) is a situation that can occur when a disk device either fails or is removed from the vSphere host in an uncontrolled fashion. PDL detects if a disk device has been permanently removed, that is, the device will not return based on SCSI sense codes.
When the device enters this PDL state, the vSphere host can take action to prevent directing any further, unnecessary I/O to this device. This alleviates other conditions that might arise on the host as a result of this unnecessary I/O.
Starting with vSphere 5.5 and above, a new feature called PDL AutoRemove is introduced. This feature automatically removes a device from a host when it enters a PDL state. Because vSphere ESXi hosts have a limit of 255 disk devices per host, a device that is in a PDL state can no longer accept I/O, but can still occupy one of the available disk device spaces. Therefore, it is better to remove the device from the host.
PDL AutoRemove occurs only if there are no open handles left on the device. The auto-remove takes place when the last handle on the device closes. Owing to this, if the device recovers, or if it is re-added after having been inadvertently removed, it would be treated as a new device.
The PDL AutoRemove feature is enabled by default across all supported versions of ESXi 6.7.x and 7.0.x.
To verify this, run this command to validate the current status of the setting:
esxcli system settings advanced list -o /Disk/AutoremoveOnPDL
Path: /Disk/AutoremoveOnPDL
Type: integer
Int Value: 1
Default Int Value: 1
Min Value: 0
Max Value: 1
String Value:
Default String Value:
Valid Characters:
Description: Autoremove paths to a disk that is in PDL (Permanent Device Loss)
When the device enters this PDL state, the vSphere host can take action to prevent directing any further, unnecessary I/O to this device. This alleviates other conditions that might arise on the host as a result of this unnecessary I/O.
Starting with vSphere 5.5 and above, a new feature called PDL AutoRemove is introduced. This feature automatically removes a device from a host when it enters a PDL state. Because vSphere ESXi hosts have a limit of 255 disk devices per host, a device that is in a PDL state can no longer accept I/O, but can still occupy one of the available disk device spaces. Therefore, it is better to remove the device from the host.
PDL AutoRemove occurs only if there are no open handles left on the device. The auto-remove takes place when the last handle on the device closes. Owing to this, if the device recovers, or if it is re-added after having been inadvertently removed, it would be treated as a new device.
The PDL AutoRemove feature is enabled by default across all supported versions of ESXi 6.7.x and 7.0.x.
To verify this, run this command to validate the current status of the setting:
esxcli system settings advanced list -o /Disk/AutoremoveOnPDL
Path: /Disk/AutoremoveOnPDL
Type: integer
Int Value: 1
Default Int Value: 1
Min Value: 0
Max Value: 1
String Value:
Default String Value:
Valid Characters:
Description: Autoremove paths to a disk that is in PDL (Permanent Device Loss)
Note: VMware does not recommend to have the PDL AutoRemove feature disabled. Unless explicitly requested by your Storage Vendor.
From vSphere 6.x and above, the response to a PDL is different. Due to this change, VMware recommends you not to disable the AutoRemoveOnPDL feature in vSphere 6.x.
In vSphere 6.x, the expectation is that a device in a PDL state will not return. Therefore, the device needs to be removed from the ESXi host, before it can be recovered. If the AutoRemoveOnPDL feature is disabled, a manual rescan is required to remove the device while in a PDL state.
In vSphere 6.x, the expectation is that a device in a PDL state will not return. Therefore, the device needs to be removed from the ESXi host, before it can be recovered. If the AutoRemoveOnPDL feature is disabled, a manual rescan is required to remove the device while in a PDL state.
Note: For vSphere Metro Storage Cluster (vMSC) environments, VMware recommends to have AutoremoveOnPDL set to 1 explicitly for vSphere 6.x.
If you wish to proceed with disabling the AutoRemoveOnPDL feature, apply these steps:
- Connect to the ESXi host through SSH.
- Run this command to disable PDL AutoRemove:
esxcli system settings advanced set -o "/Disk/AutoremoveOnPDL" -i 0
- There is no guarantee of data integrity can be given if a device returns from a PDL.
- To re-enable the AutoRemove feature, run this command from a shell session to the ESXi host:
esxcli system settings advanced set -o "/Disk/AutoremoveOnPDL" -i 1
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