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Lost redundant path to storage device & Path redundancy to the storage device is degraded

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Lost redundant path to storage device:
  • ESX host has lost all the redundant paths to a storage device and there is only one active path left
  • The Task and Events tab of the ESX host on the vSphere Client reports this error under events:

    Lost path redundancy to storage device DeviceName. Path vmhbaN:Cx:Ty:Lz is down. Affected datastores: DatastoreName

  • The ESX host and virtual machines can still access the storage device through the single active path that remains
Solution

If vmhba3:C0:T1:L7 is the last redundant path to go down for a specified storage device, you see this message:

Lost path redundancy to storage device naa.xxxxxxxx. Path vmhba3:C0:T1:L7 is down. Affected datastores: Datastore1

The situation indicates a single point of failure and poses a performance impact in the virtual machines currently accessing the storage device.

The storage device reading vmhba3:C0:T1:L7 in the example contains several potential failure points:

  • vmhba35 – HBA (Host Bus Adapter)
  • C1 – Channel
  • T0 – Target (Storage processor port)
  • L7 – LUN (Logical Unit Number or Disk Unit)
Path redundancy to the storage device is degraded
  • ESX host has lost a redundant path to a storage device and there are still more than one active paths left.
  • The Task and Events tab of the ESX host on the vSphere Client reports the error:

    Path redundancy to storage device DeviceName degraded. Path vmhbaN:Cx:Ty:Lz is down. Affected datastores: DatastoreName

  • ESX host and virtual machines continue to access the storage device through the remaining active paths.
Solution

If vmhba3:C0:T1:L7, which is one of the many active paths to a specified storage device, goes down, you see this message:

Path redundancy to storage device naa.xxxxxx degraded. Path vmhba3:C0:T1:L7 is down. Affected datastores: Datastore1

This situation indicates a single point of failure and poses a performance impact in the virtual machines currently accessing the storage device.

The storage device reading vmhba3:C0:T1:L7 in the example contains several potential failure points:

  • vmhba3 – HBA (Host Bus Adapter)
  • C0 – Channel 0
  • T1 – Target 1 (Storage processor port)
  • L7 – LUN 7 (Logical Unit Number or Disk Unit)

Examples :

Taking an example of one LUN in each array :

1: Tegile : We have 2 paths form vmbha3 and vmhba2 ,vmhba3 went down and we are left with one path here . ESXi host has lost all the redundant paths to a storage device and there is only one active path left. Hence , the error “Lost path redundancy to storage”

naa.61c5a0b06b59c80100005d0bb7990010:
Device Display Name: TEGILE Fibre Channel Disk (naa.61c5a0b06b59c80100005d0bb7990010)
Storage Array Type: VMW_SATP_ALUA
Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=9,TPG_state=AO}{TPG_id=8,TPG_state=AO}}
Path Selection Policy: VMW_PSP_RR
Path Selection Policy Device Config: {policy=rr,iops=1,bytes=10485760,useANO=0; lastPathIndex=1: NumIOsPending=0,numBytesPending=0}
Path Selection Policy Device Custom Config:
Working Paths: vmhba2:C0:T6:L10, vmhba3:C0:T6:L10
Is USB: false

2019-07-29T21:42:03.978Z: [scsiCorrelator] 8734477455956us: [esx.problem.storage.redundancy.lost] Lost path redundancy to storage device naa.61c5a0b06b59c80100005d0bb7990010. Path vmhba3:C0:T6:L10 is down. Affected datastores: “TowerVCL2_Tier1_STTEG1_DS11”.
2019-07-29T21:46:57.865Z: [scsiCorrelator] 8734771343649us: [esx.clear.storage.redundancy.restored] Path redundancy to storage device naa.61c5a0b06b59c80100005d0bb7990010 (Datastores: “TowerVCL2_Tier1_STTEG1_DS11”) restored. Path vmhba3:C0:T6:L10 is active again.

2: Pure: 2 paths went down from vmbha3 however we donot see vmhba2 impacted here so the paths on vmhba2 were active .So,ESXi host has lost a redundant path to a storage device and there are still more than one active paths left.Hence the error “Path redundancy to storage device”

naa.624a93702bd54de17bba40e700011022:
Device Display Name: PURE Fibre Channel Disk (naa.624a93702bd54de17bba40e700011022)
Storage Array Type: VMW_SATP_ALUA
Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=0,TPG_state=AO}}
Path Selection Policy: VMW_PSP_RR
Path Selection Policy Device Config: {policy=iops,iops=1,bytes=10485760,useANO=0; lastPathIndex=0: NumIOsPending=0,numBytesPending=0}
Path Selection Policy Device Custom Config:
Working Paths: vmhba2:C0:T4:L254, vmhba3:C0:T5:L254, vmhba2:C0:T5:L254, vmhba3:C0:T4:L254
Is USB: false

2019-07-29T21:42:03.955Z: [scsiCorrelator] 8734477433429us: [esx.problem.storage.redundancy.degraded] Path redundancy to storage device naa.624a93702bd54de17bba40e700011022 degraded. Path vmhba3:C0:T4:L254 is down. Affected datastores: “TowerVCL2_Tier0_STpureC_DS9”.
2019-07-29T21:42:03.967Z: [scsiCorrelator] 8734477445626us: [esx.problem.storage.redundancy.degraded] Path redundancy to storage device naa.624a93702bd54de17bba40e700011022 degraded. Path vmhba3:C0:T5:L254 is down. Affected datastores: “TowerVCL2_Tier0_STpureC_DS9”.
2019-07-29T21:46:57.928Z: [scsiCorrelator] 8734771405808us: [esx.clear.storage.redundancy.restored] Path redundancy to storage device naa.624a93702bd54de17bba40e700011022 (Datastores: “TowerVCL2_Tier0_STpureC_DS9”) restored. Path vmhba3:C0:T4:L254 is active again.

3: COMPELNT: vmbha3 both the paths went down , and vmhba 2 never went down ,hence there was access . So,ESXi host has lost a redundant path to a storage device and there are still more than one active paths left. Hence the error “Path redundancy to storage device”

naa.6000d310007ef5000000000000000096:
Device Display Name: COMPELNT Fibre Channel Disk (naa.6000d310007ef5000000000000000096)
Storage Array Type: VMW_SATP_ALUA
Storage Array Type Device Config: {implicit_support=on; explicit_support=off; explicit_allow=on; alua_followover=on; action_OnRetryErrors=off; {TPG_id=61486,TPG_state=AO}{TPG_id=61490,TPG_state=AO}{TPG_id=61485,TPG_state=AO}{TPG_id=61489,TPG_state=AO}}
Path Selection Policy: VMW_PSP_RR
Path Selection Policy Device Config: {policy=iops,iops=1,bytes=10485760,useANO=0; lastPathIndex=2: NumIOsPending=0,numBytesPending=0}
Path Selection Policy Device Custom Config:
Working Paths: vmhba3:C0:T2:L6, vmhba3:C0:T3:L6, vmhba2:C0:T2:L6, vmhba2:C0:T3:L6
Is USB: false

2019-07-29T21:42:03.912Z: [scsiCorrelator] 8734477390138us: [esx.problem.storage.redundancy.degraded] Path redundancy to storage device naa.6000d310007ef5000000000000000096 degraded. Path vmhba3:C0:T2:L6 is down. Affected datastores: “TowerVCL2_Tier1_STcomp1_DS6”.
2019-07-29T21:42:03.916Z: [scsiCorrelator] 8734477394585us: [esx.problem.storage.redundancy.degraded] Path redundancy to storage device naa.6000d310007ef5000000000000000096 degraded. Path vmhba3:C0:T3:L6 is down. Affected datastores: “TowerVCL2_Tier1_STcomp1_DS6”.
2019-07-29T21:46:57.877Z: [scsiCorrelator] 8734771354867us: [esx.clear.storage.redundancy.restored] Path redundancy to storage device naa.6000d310007ef5000000000000000096 (Datastores: “TowerVCL2_Tier1_STcomp1_DS6”) restored. Path vmhba3:C0:T2:L6 is active again.

To fix the issue please follow:

https://kb.vmware.com/s/article/1009554

https://kb.vmware.com/s/article/1009555

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