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    Logical Volume Error: mount: special device /dev/mapper/DBBACKLOGS-archlogs1 does not exist

    LVM Logical Volume Error: mount: special device /dev/mapper/DBBACKLOGS-archlogs1 does not exist


    Centos
    CentOS

    After a storage issue when we got back the volumes, most of them were giving some strange errors. This one is one of such issue. The physical volume was visible in the system, however the Logical volume was not present. 

    To fix the situation we need to do the following:


    Option 1: 

    Scan the Logical Volume. Check if it is active.

    [root@thedbserver ~]# lvscan
      ACTIVE            '/dev/TORBCK/backup' [5.00 TiB] inherit
      ACTIVE            '/dev/DBBACKLOGS/archlogs1' [5.00 TiB] inherit
      
    Try to activate the Logical Volume.


    [root@thedbserver ~]# lvchange -ay -v /dev/DBBACKLOGS/archlogs1
        Using logical volume(s) on command line.
        Activating logical volume "archlogs1".
        activation/volume_list configuration setting not defined: Checking only host tags for DBBACKLOGS/archlogs1.

    Check the Logical Volume status and try to mount the File system. 


    [root@thedbserver ~]# lvs
      LV                 VG        Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
      backup             TORBCK   -wi-ao----   5.00t
      archlogs1          DBBACKLOGS -wi-a-----   5.00t

    [root@thedbserver ~]# mount -a
    mount: special device /dev/mapper/DBBACKLOGS-archlogs1 does not exist



    Option 2: 
    Check the devices associated with logical volume.
    [root@thedbserver ~]# lvs -a -o+devices
      LV                 VG        Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert Devices
      backup             TORBCK   -wi-ao----   5.00t                                                     /dev/mapper/STOR02-EXA2-BCK01(0
      archlogs1          DBBACKLOGS -wi-a-----   5.00t                                                     /dev/mapper/STOR03-EXA2-LOGS02(
      
     Check Logical volume output and check if open is 0 or 1. 

    [root@thedbserver ~]# lvdisplay  /dev/DBBACKLOGS/archlogs1
      --- Logical volume ---
      LV Path                /dev/DBBACKLOGS/archlogs1
      LV Name                archlogs1
      VG Name                DBBACKLOGS
      LV UUID                
      LV Write Access        read/write
      LV Creation host, time thedbserver.local, 2016-05-02 21:05:40 +0200
      LV Status              available
      # open                 0
      LV Size                5.00 TiB
      Current LE             1310719
      Segments               1
      Allocation             inherit
      Read ahead sectors     auto
      - currently set to     256
      Block device           252:8

    List out all the scsi devices.


    [root@thedbserver ~]# lsscsi
    [0:2:0:0]    disk    LSI      MR9361-8i        4.23  /dev/sda
    [23:0:0:7]   disk    MSFT     STORSIMPLE 8600  222   /dev/sdb
    [25:0:0:9]   disk    MSFT     STORSIMPLE 8100  222  /dev/sdc
    [root@thedbserver ~]#

    Now deactivate the logical volume.
    [root@thedbserver ~]# lvchange -an DBBACKLOGS
    [root@thedbserver ~]#

    Check Logical Volume.


    [root@thedbserver ~]# lvs
      LV                 VG        Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
      backup             TORBCK   -wi-ao----   5.00t
      archlogs1          DBBACKLOGS -wi-------   5.00t
      
     Now Export the VG.

    [root@thedbserver ~]# vgexport DBBACKLOGS
      Volume group "DBBACKLOGS" successfully exported
    [root@thedbserver ~]#
    [root@thedbserver ~]#

    Check the VG's again.
    [root@thedbserver ~]# vgs
      VG        #PV #LV #SN Attr   VSize VFree
      STORBCK     1   1   0 wz--n- 5.00t      0
      DBBACKLOGS   1   1   0 wzx-n- 5.00t      0
      VGExaDb     2   6   0 wz--n- 1.63t 788.08g
    [root@thedbserver ~]#
    [root@thedbserver ~]#

    Now scan the vgs again.
    [root@thedbserver ~]# vgscan
      Reading all physical volumes.  This may take a while...
      Found volume group "TORBCK" using metadata type lvm2
      Found exported volume group "DBBACKLOGS" using metadata type lvm2
      [root@thedbserver ~]# vgs
      VG        #PV #LV #SN Attr   VSize VFree
      TORBCK     1   1   0 wz--n- 5.00t      0
      DBBACKLOGS   1   1   0 wzx-n- 5.00t      0
      [root@thedbserver ~]#
    [root@thedbserver ~]#

    Now import the Concerned VG.
    [root@thedbserver ~]# vgimport DBBACKLOGS
      Volume group "DBBACKLOGS" successfully imported
    [root@thedbserver ~]#
    [root@thedbserver ~]#

    Check the VG's again.


    [root@thedbserver ~]# vgs
      VG        #PV #LV #SN Attr   VSize VFree
      TORBCK     1   1   0 wz--n- 5.00t      0
      DBBACKLOGS   1   1   0 wz--n- 5.00t      0
     [root@thedbserver ~]#
    [root@thedbserver ~]#

    Now activate the Logical Volume.


    [root@thedbserver ~]# lvchange -ay DBBACKLOGS

    Now you can mount the File system.


    [root@thedbserver ~]# mount -a

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