VMware: vSAN Physical Disk Troubleshooting Guide

Checking for vSAN Physical Disk status from the Web UI:

Connect to vCenter Server Web Client and check the disk status from:
 
Inventory > Host and Clusters > vSAN Cluster > Configure > vSAN > Disk Management

Picture 1: vSAN Disk Management view

Select the affected host and then expand the view disk section:

Picture 2: vSAN Disk Group view

Here you can verify if a disk is detected as:
 
Unhealthy
Unmounted
0 Capacity
Permanent Disk Failure
Disk Down
Disk Absent
 
Also, check for disk-related alarms triggered from the vSAN Skyline Health section:
 
Inventory > Host and Clusters > vSAN Cluster > Monitor > vSAN > Skyline Health > Physical disk

Picture 3: Skyline Health view

Here you can verify if any of the following alarms is triggered:
 
Impending permanent disk failure, data is being evacuated (Health state - Yellow).
Impending permanent disk failure, data evacuation failed due to insufficient resources (Health state - Red).
Impending permanent disk failure, data evacuation failed due to inaccessible objects (Health state - Red).
Impending permanent disk failure, data evacuation completed (Health state - Yellow)
 
Also, you can check disk status from the affected host's Storage Devices list:
 
Inventory > Host and Clusters > vSAN Cluster > Affected vSAN ESXi Host > Configure > Storage > Storage Devices

Picture 4: Host Storage Devices view

Here you can verify if a disk status is:
 
0 Capacity
Disk Absent
Disk Unmounted
 
Verify if there is a Resync happening:
 
Inventory > Host and Clusters > vSAN Cluster > Monitor > vSAN > Resyncing Objects:

Picture 5: Resyncing Objects view

 
Verify the status of vSAN Objects:
 
Inventory > Host and Clusters > vSAN Cluster > Monitor > vSAN > Skyline Health > Data > vSAN object health

Picture 6: vSAN object health view

 
The next step is to gather more information about the issue over CLI and checking the logs:

Checking for vSAN Physical Disk status from CLI:

Connect over SSH to the affected host and run the following commands:
 

vdq -qH

Check on the "IsPDL" (permanent device loss) parameter. If it is equal 1, the disk is lost.
 
Example:
 

DiskResults:
 DiskResult[0]:
 Name: naa.600508b1001c4b820b4d80f9f8acfa95
 VSANUUID: 5294bbd8-67c4-c545-3952-7711e365f7fa
 State: In-use for VSAN
 ChecksumSupport: 0
 Reason: Non-local disk
 IsSSD?: 0
IsCapacityFlash?: 0
 IsPDL?: 0
 <<truncated>>
 DiskResult[18]:
 Name:
 VSANUUID: 5227c17e-ec64-de76-c10e-c272102beba7
 State: In-use for VSAN
 ChecksumSupport: 0
 Reason: None
 IsSSD?: 0
IsCapacityFlash?: 0
 IsPDL?: 1

 

vdq -iH

Check if there is a missing disk from the disk group.
 
Example:
 

Mappings:
DiskMapping[0]:
SSD: naa.58ce38ee2016ffe5
MD: naa.5002538a4819e3e0
 
DiskMapping[2]:
SSD: naa.58ce38ee2016fe55
MD: naa.5002538a48199ca0
MD: naa.5002538a48199e20
MD: naa.5002538a48199e00

 

esxcli vsan storage list

Check on the "In CMMDS" parameter. If false, then communication is lost to disk.
 
Example:
 

Device: Unknown
Display Name: Unknown
Is SSD: false
VSAN UUID: 529cadbc-acd1-b588-8643-68336d5512d6
VSAN Disk Group UUID:
VSAN Disk Group Name:
Used by this host: false
In CMMDS: false
On-disk format version: <Unknown>
Deduplication: false
Compression: false
Checksum:
Checksum OK: false
Is Capacity Tier: false

 

for i in `esxcli  storage core device list | grep ^naa` ; do echo $i; esxcli storage core device smart get -d $i; done.

Check for read/write errors with the smart get command.
 
Example:
 

naa.55cd2e404c1f35a1
Parameter                   Value  Threshold  Worst  Raw
--------------------------  -----  ---------  -----  ---
Health Status               OK     N/A        N/A    N/A
Media Wearout Indicator     100    0          100    86
Read Error Count            130    39         130    133
Power-on Hours              100    0          100    110
Power Cycle Count           100    0          100    106
Drive Temperature           100    0          100    26
Uncorrectable Sector Count  100    0          100    0

naa.55cd2e404c1f35a5
Parameter                   Value  Threshold  Worst  Raw
--------------------------  -----  ---------  -----  ---
Health Status               OK     N/A        N/A    N/A
Media Wearout Indicator     100    0          100    10
Read Error Count            130    39         130    53
Power-on Hours              100    0          100    110
Power Cycle Count           100    0          100    106
Drive Temperature           100    0          100    27
Uncorrectable Sector Count  100    0          100    0

 

esxcli vsan storage list | grep "VSAN Disk Group UUID:" | sort | uniq -c

Check for available disk groups.
 
Example:
 

      2    VSAN Disk Group UUID: 5203424c-ee56-497d-75d1-fcf73ae997cb
      2    VSAN Disk Group UUID: 52af8e5c-77d1-b552-3310-ec5fef09edf4

 

while true;do echo " ****************************************** "; echo "" > /tmp/resyncStats.txt ;cmmds-tool find -t DOM_OBJECT -f json |grep uuid |awk -F \" '{print $4}' |while read i;do pendingResync=$(cmmds-tool  find -t DOM_OBJECT -f json -u $i|grep -o "\"bytesToSync\": [0-9]*,"|awk -F " |," '{sum+=$2} END{print sum / 1024 / 1024 / 1024;}');if [ ${#pendingResync} -ne 1 ]; then echo "$i: $pendingResync GiB";fi;done |tee -a /tmp/resyncStats.txt;total=$(cat /tmp/resyncStats.txt |awk '{sum+=$2} END{print sum}');echo "Total: $total GiB" |tee -aa /tmp/resyncStats.txt;total=$(cat /tmp/resyncStats.txt  |grep Total);totalObj=$(cat /tmp/resyncStats.txt|grep -vE " 0 GiB|Total"|wc -l);echo "`date +%Y-%m-%dT%H:%M:%SZ` $total ($totalObj objects)" >> /tmp/totalHistory.txt; echo `date `; sleep 60; done

Check if there are ongoing or stuck resync operations.
 
Example:
 

Total: 0 GiB
Mon Feb 13 17:32:06 UTC 2023

Press Ctrl+C to stop command.
 

cmmds-tool find -f python | grep CONFIG_STATUS -B 4 -A 6 | grep 'uuid\|content' | grep -o 'state\\\":\ [0-9]*' | sort | uniq -c

Check the state of the components.
 
Healthy -- state 7
Inaccessible -- state 13
Absent or Degraded -- state 15
 
Example:
 

    425 state\": 7

 
How to identify where the failed SSD or HARD DRIVE is located over CLI:
 
List all available devices:

esxcli storage core device list | grep "naa" | awk '{print $1}' | grep "naa"

Example:
 

naa.5000c500852df8d3
naa.55cd2e404c1f35a1
naa.55cd2e404c1f35a5
naa.5000c500852dd5e7

Check the location using each disk naa from the list:

esxcli storage core device physical get -d

 
Example:
 

esxcli storage core device physical get -d naa.5000c500852df8d3
esxcli storage core device physical get -d naa.55cd2e404c1f35a1
esxcli storage core device physical get -d naa.55cd2e404c1f35a5
esxcli storage core device physical get -d naa.5000c500852dd5e7
 
   Physical Location: enclosure 65535 slot 0
   Physical Location: enclosure 65535 slot 1
   Physical Location: enclosure 65535 slot 2
   Physical Location: enclosure 65535 slot 3

How to identify the failed HARD DRIVE or SSD if the device name is missing:

It is possible that the failed disk is not detected and unable to identify using the corresponding naa. In this scenario, it is needed to locate all disks, and the one that is not physically located would be the one that failed.

Here is a script that can be used to perform the task slightly quicker:

echo "=============Physical disks placement=============="
echo ""
esxcli storage core device list | grep "naa" | awk '{print $1}' | grep "naa" | while read in; do
echo "$in"
esxcli storage core device physical get -d "$in"
sleep 1
echo "===================================================="
done

vSAN relevant logs for storage-related issues:
 
/var/log/vmkernel.log
Issues reading and writing to vSAN disks, vSAN host heartbeats, PDLs, SCSI sense codes and I/O requests (Reads/Writes), and cluster membership information.
 
Example:
 

2021-06-22T12:02:08.408Z cpu30:1001397101)ScsiDeviceIO: PsaScsiDeviceTimeoutHandlerFn:12834: TaskMgmt op to cancel IO succeeded for device naa.55cd2e404b7736d0 and the IO did not complete. WorldId 0, Cmd 0x28, CmdSN = 0x428.Cancelling of IO will be
2021-06-22T12:02:08.408Z cpu30:1001397101)retried.

/var/log/vobd.log
Reports on disk health, permanent device lost disks (PDLs), disk latency, and reports on when a host enters and exits maintenance mode.
 
Example:
 

2022-05-31T11:42:46.065Z: [vSANCorrelator] 10605891965954us: [vob.vsan.lsom.devicerepair] vSAN device 521a74ce-c980-c16c-ff3d-38a036233daf is being repaired due to I/O failures, and will be out of service until the repair is complete. If the device is part of a dedup disk group, the entire disk group will be out of service until the repair is complete.
2022-05-31T11:42:46.065Z: [vSANCorrelator] 10606062774178us: [esx.problem.vob.vsan.lsom.devicerepair] Device 521a74ce-c980-c16c-ff3d-38a036233daf is in offline state and is getting repaired

/var/log/vsandevicemonitord.log
It helps you to determine if the disk was marked unhealthy due to excessive log congestion or I/O latencies.
 
Example:
 

INFO vsandevicemonitord WARNING - WRITE Average Latency on VSAN device naa.50000xxxxxxxx has exceeded threshold value 2000000 us 2 times.
INFO vsandevicemonitord Tier 2 (naa.50000xxxxxxxx) as unhealthy

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