[linux-lvm] Fwd: Millions of mismatches after scrubbing lvm raid

Roman Dissauer roman at dissauer.net
Fri Mar 27 12:06:19 UTC 2015


Hi all,

can anybody help me with this?

Thanks,
Roman Dissauer

> Anfang der weitergeleiteten Nachricht:
> 
> Betreff: [linux-lvm] Millions of mismatches after scrubbing lvm raid
> Von: Roman Dissauer <roman at dissauer.net>
> Datum: 19. März 2015 22:54:02 MEZ
> An: linux-lvm at redhat.com
> 
> Hi all,
> 
> I’m on centos 7 and have several logical volumes on my machine. Yesterday I scrubbed the raid1/raid10 logical volumes for the first time after 6 months. Scrubbing reported multi million mismatches on three of my logical volumes (the older ones). Recently created lvs didn’t have any mismatches though. Now I raised some questions:
> 
> 1. Is this a normal behaviour of raid1/raid10 to have this much mismatches?
> 2. Is it safe to do "lvchange --syncaction repair“ on this logical volumes?
> 3. How does lvm know which one is the „good“ side of the raid1?
> 4. Is it a good idea to do „lvchange --resync“ from time to time?
> 5. Is it more reliable to change the lvm from raid10 to raid6?
> 
> maybe someone can help me answering my questions.
> enclosed you’ll find some more information.
> 
> Thanks,
> Roman Dissauer
> 
> 
> Here is the scrub output:
>  LV       VG     Attr       Start SSize   #Str Type    Stripe  Chunk Mismatches SyncAction Cpy%Sync
>  data     vg0    rwi-aor-m-    0    3,49t    4 raid10  512,00k    0   895444480idle         100,00
>  owncloud vg0    rwi-aor-m-    0  250,00g    2 raid1        0     0   285961472 idle         100,00
>  root     vg0    rwi-aor-m-    0   30,00g    4 raid1        0     0    16501376 idle         100,00
> 
> on data this is about 0.1% mismatch of the volume
> on owncloud this is about 0.4% mismatch of the volume
> on root this is about 0.2% mismatch of the volume
> 
> 
> And here the output of the system storage manager:
> ---------------------------------------------------------------
> Device          Free       Used      Total  Pool    Mount point
> ---------------------------------------------------------------
> /dev/sda                           2.73 TB          PARTITIONED
> /dev/sda1  873.50 GB    1.88 TB    2.73 TB  vg0                
> /dev/sdb                           2.73 TB                     
> /dev/sdb1  860.84 GB    1.89 TB    2.73 TB  vg0                
> /dev/sdc                           2.73 TB                     
> /dev/sdc1   10.82 GB    2.72 TB    2.73 TB  vg0                
> /dev/sdd                           2.73 TB                     
> /dev/sdd1   10.82 GB    2.72 TB    2.73 TB  vg0                
> /dev/sde                           7.32 GB                     
> /dev/sde1                        500.00 MB          /boot      
> /dev/sdg     0.00 KB  931.51 GB  931.51 GB  backup             
> /dev/sdh     0.00 KB    2.73 TB    2.73 TB  backup             
> ---------------------------------------------------------------
> -------------------------------------------------
> Pool    Type  Devices     Free     Used     Total  
> -------------------------------------------------
> backup  lvm   2        0.00 KB  3.64 TB   3.64 TB  
> vg0     lvm   4        1.71 TB  9.20 TB  10.92 TB  
> -------------------------------------------------
> -------------------------------------------------------------------------------------------
> Volume              Pool    Volume size  FS      FS size       Free  Type     Mount point  
> -------------------------------------------------------------------------------------------
> /dev/backup/backup  backup      3.64 TB  ext4    3.64 TB  509.38 GB  linear   /backup      
> /dev/vg0/data       vg0         3.49 TB  ext4    3.49 TB  595.34 GB  raid10   /data        
> /dev/vg0/home       vg0       200.00 GB  ext4  200.00 GB  128.58 GB  raid10   /home        
> /dev/vg0/owncloud   vg0       250.00 GB  xfs   249.99 GB  145.01 GB  raid1    /var/owncloud
> /dev/vg0/jail       vg0        10.00 GB  ext4   10.00 GB    6.71 GB  raid1    /jail        
> /dev/vg0/fotos      vg0       500.00 GB  ext4  500.00 GB  456.07 GB  raid1    /fotos       
> /dev/vg0/virtswap   vg0        20.00 GB  ext4   20.00 GB   17.89 GB  striped  /virt/swap   
> /dev/vg0/iso        vg0        10.00 GB  ext4   10.00 GB    8.05 GB  linear   /virt/iso    
> /dev/vg0/images     vg0       100.00 GB  ext4  100.00 GB   83.09 GB  raid1    /virt/images 
> /dev/vg0/root       vg0        30.00 GB  xfs    29.99 GB    5.79 GB  raid1    /            
> /dev/vg0/swap       vg0         8.00 GB                              striped               
> /dev/sde1                     500.00 MB  xfs   496.67 MB  240.59 MB           /boot        
> -------------------------------------------------------------------------------------------
> 
> Disks are WD RED 3TB
> 
> and here some revision numbers:
> uname -r
> 3.10.0-123.20.1.el7.x86_64
> 
> lvm version
>  LVM version:     2.02.105(2)-RHEL7 (2014-03-26)
>  Library version: 1.02.84-RHEL7 (2014-03-26)
>  Driver version:  4.27.0
> 
> 





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