Re: lvm2 raid volumes

Heinz Mauelshagen <heinzm@redhat.com> · Wed, 3 Aug 2016 15:10:00 +0200



    On 08/03/2016 12:49 AM, Steve Dainard
      wrote:

    
      Hello,
        

        What are the methods for checking/monitoring a RAID LV?
      
    
    Hi Stev,

    
    see dmeventd (device-mapper monitoring daemon) and read lvm.conf WRT
    raid_fault_policy.

    
    dmeventd provides warn or allocate mode allowing to either just warn
    about a RAID DataLV

    or MetaLV failure or actively repair such failures. You'll find
    related messages in the system log.

    
        The Cpy%Sync field seems promising here:
        

          # lvs
            LV    VG           Attr       LSize   Pool Origin Data%
             Meta%  Move Log Cpy%Sync Convert
            raid1 test         rwi-aor--- 100.00m                  
                             100.00          

          
            raid6 test         rwi-aor--- 108.00m                  
                             100.00          

          
    The Cyp%Sync field tells you about the resynchronization progress,
    i.e. the initial mirroring of

    all data blocks in a raid1/10 or the initial calculation and storing
    of parity blocks in raid4/5/6.

    
    It should display a percentage value as in:

    
    # lvs -o+devices iscsi

      LV   VG          Attr       LSize   Pool Origin Data%  Meta%  Move
    Log Cpy%Sync Convert
Devices                                                                           
    

      r    iscsi rwi-a-r--- 4.00t                                   
    0.03            
r_rimage_0(0),r_rimage_1(0),r_rimage_2(0),r_rimage_3(0),r_rimage_4(0),r_rimage_5(0)

    
    Do you have a clean installation?

    Try reinstalling lvm2 and device-mapper\*

    
          # pvs
            PV         VG           Fmt  Attr PSize    PFree  
            /dev/vdb   test         lvm2 a--  1020.00m 876.00m

          
            /dev/vdc   test         lvm2 a--  1020.00m 876.00m
            /dev/vdd   test         lvm2 a--  1020.00m 980.00m
            /dev/vde   test         lvm2 a--  1020.00m 980.00m
            /dev/vdf   test         lvm2 a--  1020.00m 980.00m
        
        
        But testing in a VM by removing a disk does not change the
          output of lvs:
        
          
          # pvs
            WARNING: Device for PV
            S5xFZ7-mLaH-GNQP-ujWh-Zbkt-Ww3u-J0aKUJ not found or rejected
            by a filter.
            PV             VG           Fmt  Attr PSize    PFree  
            /dev/vdb       test         lvm2 a--  1020.00m 876.00m

          
            /dev/vdc       test         lvm2 a--  1020.00m 876.00m
            /dev/vdd       test         lvm2 a--  1020.00m 980.00m
            /dev/vde       test         lvm2 a--  1020.00m 980.00m
            unknown device test         lvm2 a-m  1020.00m 980.00m
        
        
          # lvs
            WARNING: Device for PV
            S5xFZ7-mLaH-GNQP-ujWh-Zbkt-Ww3u-J0aKUJ not found or rejected
            by a filter.
            LV    VG           Attr       LSize   Pool Origin Data%
             Meta%  Move Log Cpy%Sync Convert
            raid1 test         rwi-aor--- 100.00m                  
                             100.00          
            raid6 test         rwi-aor-p- 108.00m                  
                             100.00          
        
        
        My end goal is to write a nagios check to monitor for disk
          failures.
      
    
    You may want to start with the Nagios checkvolmanager plugin...

    
    Heinz

    
        Thanks,
        Steve
      
      
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