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Unmounting a datastore used for Host Cache on ESXi 5.5 fails (2069171)

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Symptoms

  • Unmounting a datastore using vSphere client, which was used for Host Cache on the ESXi 5.5 host fails with the error:

    Cannot unmount volume 'Datastore Name: vm3:SSD VMFS uuid: 517c9950-10f30962-931f-00304830a1ea' because file system is busy. Correct the problem and retry the operation.

  • When you browse the datastore, you see these two files:

    • vsantraces--2013-09-25T15h48m12s468.gz
    • vsantraces.index

  •  The processes running on the host for vsantraces with the command  lsof | grep vsantrace results in output similar to:

    7776930     vsantraced            CHAR                        0   /dev/null
    7776930     vsantraced            CHAR                        1   /dev/null
    7776930     vsantraced            CHAR                        2   /dev/null
    7776930     vsantraced            FILE                        3   /vmfs/volumes/517c9950-10f30962-931f-00304830a1ea/vsantraces/vsantraces--2013-09-25T17h06m33s095.gz
    7776930     vsantraced            MMAP                       -1   /bin/logchannellogger (prot:--/len:19056)
    7776930     vsantraced            MMAP                       -1   /bin/logchannellogger (prot:--/len:4352)
    7776930     vsantraced            MMAP                       -1   /lib/ld-linux.so.2 (prot:--/len:112600)
    7776930     vsantraced            MMAP                       -1   /lib/ld-linux.so.2 (prot:--/len:6232)
    ......

  • If you try to delete the partition containing the datastore use for Host Cache, you see the error:

    partedUtil delete /vmfs/devices/disks/t10.ATA_____OCZ2DAGILITY3____________________________OCZ2D72T0B86HWM2WE1X9 1
    Error: Read-only file system during write on /dev/disks/t10.ATA_____OCZ2DAGILITY3____________________________OCZ2D72T0B86HWM2WE1X9
    Unable to delete partition 1 from device /vmfs/devices/disks/t10.ATA_____OCZ2DAGILITY3____________________________OCZ2D72T0B86HWM2WE1X9

  • VMware vCenter Site Recovery Manager (SRM) Failover operations fail during the storage unmount phase
  • SRM Test Failover cleanup operations fail during the storage unmount phase

Purpose

The issue of unmounting a datastore causing the error Cannot unmount volume <Datastore> because file system is busy is resolved in ESXi 5.5 Update 2 and later versions.

Cause

This issue occurs when the VSAN module actively stores the traces needed to debug any VSAN related issues on VMFS datastores. Some VSAN modules do basic initialization work even if VSAN is not used. This prevents unmounting the datatstore from the host.

Resolution

This issue is resolved in ESXi 5.5 Update 2 and later versions, available at VMware Downloads. For more information, see the VMware ESXi 5.5 Update 2 Release Notes.

If you cannot upgrade, perform one of these options to work around this issue:

If you are not using VSAN:
  1. If VSAN is not used in your ESXi host, run this command to stop the vsantraces:

    #/etc/init.d/vsantraced stop

  2. Perform a Refresh for Storage.
  3. Unmount the datastore.
  4. Run this command to start the service:

    #/etc/init.d/vsantraced start

Note: Run this command to permanently turn off the service :
chkconfig vsantraced off

If you are using VSAN:
  1. If you are using VSAN on the ESXi host, run this command to change the VSAN trace location:

    # esxcli vsan trace set -p datastore_name

  2. Unmount the datastore.

Additional Information

You see the error:

Cannot unmount volume 'Datastore Name: vm3:SSD VMFS uuid: 517c9950-10f30962-931f-00304830a1ea' because file system is busy. Correct the problem and retry the operation."

You see this message when:
  • Scratch for host is configured on the problem datastore. Modify the ScratchConfig value and change it to another datastore.

    For more information, see Creating a persistent scratch location for ESXi 4.x and 5.x (1033696).

  • You have an SSH session from a host and your CD to the problem datastore (or a folder in it). End the SSH session to fix the issue.
  • Coredump is configured to write to a file in the problem datastore in an ESXi 5.5 host.

    For more information, see the Set Up a File as Coredump Location section in the vSphere 5.5 Storage Guide.

    Run this command to configure to a different datastore:

    esxcli system coredump file add --datastore="DatatoreName" --file="Filename" --size="200"


  • There are vpxa-worker processes running. To fix this, run the esxcli storage core device world list -d device command to display a list of such processes. If there are any, restart hostd services and then unmount the datastore.

Tags

Error: BREAK / ESXi / HOST CACHE / UNMOUNT / FAIL,cannot unmount volume datastore name because file system is busy,cannot unmount volume 'datastore name vmfs because file system is busy, Unmounting a datastore returns an error

See Also

Update History

02/27/2015 - Added details of the ESXi 5.5 Update 2 release that resolves this issue.

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