Trespassing of LUNs on the array when using Active Non-optimized (ANO) path
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Trespassing of LUNs on the array when using Active Non-optimized (ANO) path

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Article ID: 323089

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

Symptoms:
  • You observe trespassing of the LUNs on the array
  • The array has been configured correctly as per the storage vendor's recommendation.
  • The path policy on all the ESX/ESXi hosts accessing the LUN is set correctly.
  • The logs contain entries similar to:

    Aug 5 10:47:24 vmkernel: 16:13:50:01.679 cpu1:10072)NMP: nmp_CompleteCommandForPath: Command 0x2a (0x41027ef3ea40) to NMP device "naa.60060160267022007a3f86f93998de11" failed on physical path "vmhba2:C0:T0:L2" H:0x0 D:0x2 P:0x0 Valid sense data: 0x6

    Aug 5 10:47:24 vmkernel: 16:13:50:01.679 cpu1:10072)WARNING: NMP: nmp_DeviceRetryCommand: Device "naa.60060160267022007a3f86f93998de11": awaiting fast path state update for failover with I/O blocked. No prior reservation exists on the device.

    Aug 5 10:47:25 vmkernel: 16:13:50:02.684 cpu9:4227)VMW_SATP_ALUA: satp_alua_activatePaths: Activation disallowed due to follow-over.

    Aug 5 10:47:25 vmkernel: 16:13:50:02.685 cpu1:4471)WARNING: NMP: nmpDeviceAttemptFailover: Retry world failover device "naa.60060160267022007a3f86f93998de11" - issuing command 0x41027ef3ea40

    Aug 5 10:47:25 vmkernel: 16:13:50:02.685 cpu1:148055)NMP: nmpCompleteRetryForPath: Retry world recovered device "naa.60060160267022007a3f86f93998de11"

    Aug 5 10:47:25 vmkernel: 16:13:50:03.381 cpu1:145880)NMP: nmp_CompleteCommandForPath: Command 0x2a (0x41027f238d40) to NMP device "naa.60060160267022007a3f86f93998de11" failed on physical path "vmhba2:C0:T0:L2" H:0x0 D:0x2 P:0x0 Valid sense data: 0x

    Aug 5 10:47:25 vmkernel: 16:13:50:03.381 cpu1:145880)WARNING: NMP: nmp_DeviceRetryCommand: Device "naa.60060160267022007a3f86f93998de11": awaiting fast path state update for failover with I/O blocked. No prior reservation exists on the device.

    Aug 5 10:47:26 vmkernel: 16:13:50:03.684 cpu4:4471)WARNING: NMP: nmpDeviceAttemptFailover: Retry world failover device "naa.60060160267022007a3f86f93998de11" - issuing command 0x41027f238d40

    Aug 5 10:47:26 vmkernel: 16:13:50:03.685 cpu1:145865)NMP: nmpCompleteRetryForPath: Retry world recovered device "naa.60060160267022007a3f86f93998de11"


Environment

VMware vSphere ESXi 8.0
VMware vSphere ESXi 7.0
VMware vSphere ESXi 6.0
VMware vSphere ESXi 5.5
VMware vSphere ESXi 5.1

Cause

This issue occurs if the Path Selection policy (PSP) is configured to use the active non-optimized (ANO) path to issue I/O.
 
When Round Robin path selection policy (PSP_RR) is used with ALUA SATP, the default PSP_RR setting is to use only active-optimized paths if they are available.

You can override this setting with a command to include ANO paths using commands below :
 
esxcli storage nmp psp roundrobin deviceconfig set --useano=1 -d <naa of the device>

Some ALUA arrays automatically initiate a LUN failover (trespass) when enough I/O is directed to a non-optimized path. This happens so I/O is internally re-directed to an active optimized path.
 
Configuring PSP_RR to use ANO paths for such arrays may result in path thrashing and poor I/O performance.
 
You experience this issue if the array is configured with fixed path policy and the preferred path is non-optimized.

Resolution

To resolve this issue, make sure that the ANO path is not enabled for I/O.
 
To make sure that the ANO path is not enabled for I/O:
 
  1. Determine if the LUN is configured to use the ANO path using this command:

    esxcli storage nmp psp roundrobin deviceconfig get -d naa_of_device

    For example:

    esxcli storage nmp psp roundrobin deviceconfig get -d naa.600507680282008c400000000000010f

    You see output similar to:

    Byte Limit: 10485760
    Device: naa.600507680282008c400000000000010f
    IOOperation Limit: 1000
    Limit Type: Iops
    Use Active Unoptimized Paths: true

     
  2. Change this setting by running this command for the LUN that is thrashing:

    esxcli storage nmp psp roundrobin deviceconfig set --useano=0 -d device_naa

    Note: By default, when you set a path policy, the ANO value is set to 0 (false). The host uses the non-optimized path only when there are no optimized paths available.
 
There are two use-cases for using the active non-optimized ALUA paths:
  • When there are no optimized paths available.
  • During SAN boot, the multi-path driver is not loaded yet, and the simple BIOS SAN boot agent uses whatever paths it finds first.


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