[DRBD-user] out-of-sync based on AL

Cristian Zamfir zamf at dcs.gla.ac.uk
Wed Feb 14 19:31:15 CET 2007

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.



Ross S. W. Walker wrote:
>> -----Original Message-----
>> From: drbd-user-bounces at lists.linbit.com 
>> [mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of 
>> Cristian Zamfir
>> Sent: Wednesday, February 14, 2007 12:52 PM
>> To: drbd-user at lists.linbit.com
>> Subject: [DRBD-user] out-of-sync based on AL
>>
>>
>> Hi,
>>
>> I am trying to understand why the AL is marking 196MB as out of sync.
>> I have two connected primaries A and B. After they are synced 
>> I detach 
>> B. In the mean time, the disk on A is not used. I reconnect B 
>> and the on 
>> disk bit map sees that no bytes are out-of-sync, but AL marks 
>> 196MB as 
>> out-of-sync.
>>
>> In case I am misunderstandings something, can you please 
>> explain a bit 
>> how the AL works?
>>
>> This is what dmesg says on node B:
>>
>>
>> [11989.600828] drbd1: disk( UpToDate -> Diskless )
>> [11994.007899] drbd1: disk( Diskless -> Attaching )
>> [11994.040025] drbd1: Found 6 transactions (50 active extents) in 
>> activity log.
>> [11994.040067] drbd1: max_segment_size ( = BIO size ) = 32768
>> [11994.050505] drbd1: reading of bitmap took 1 jiffies
>> [11994.050759] drbd1: recounting of set bits took additional 0 jiffies
>> [11994.050780] drbd1: 0 KB marked out-of-sync by on disk bit-map.
>> [11994.050819] drbd1: Marked additional 196 MB as out-of-sync 
>> based on AL.
>> [11994.066857] drbd1: disk( Attaching -> Negotiating )
>> [11994.066942] drbd1: Writing meta data super block now.
>> [11994.067332] drbd1: conn( Connected -> WFBitMapT )
>> [11994.067358] drbd1: Writing meta data super block now.
>> [11994.079356] drbd1: conn( WFBitMapT -> WFSyncUUID )
>> [11994.090853] drbd1: conn( WFSyncUUID -> SyncTarget ) disk( 
>> Negotiating 
>> -> Inconsistent )
>> [11994.090895] drbd1: Began resync as SyncTarget (will sync 200704 KB 
>> [50176 bits set]).
>> [11994.090926] drbd1: Writing meta data super block now.
>> [12014.611505] drbd1: Resync done (total 20 sec; paused 0 
>> sec; 10032 K/sec)
>> [12014.611562] drbd1: conn( SyncTarget -> Connected ) disk( 
>> Inconsistent 
>> -> UpToDate )
>> [12014.611601] drbd1: Writing meta data super block now.
>>     
>
> Interesting, what method did you use to detach and which version are you
> running?
>
> -Ross
>
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>   
I use drbdadmin detach and drbdadmin attach.
I checked out the latest svn trunk on Mon, 11 Dec 2006 and my kernel is 
2.6.16.29.
I am using drbd on top of a 4GB LVM partition with an internal metadata 
disk.

resource "r1" {
  protocol C;
  startup {
    wfc-timeout         0;  ## Infinite!
    degr-wfc-timeout  120;  ## 2 minutes.
  }
  disk {
    on-io-error detach;
  }
  net {
    # timeout           60;
    # connect-int       10;
    # ping-int          10;
    # max-buffers     2048;
    # max-epoch-size  2048;
   allow-two-primaries ;
  }
  syncer {
    rate 10M;
    al-extents 257;
  }

  on ramree {
    device     /dev/drbd1;
    disk       /dev/vgn/vm;
    address    130.209.253.128:7789;
    meta-disk  internal;
  }

  on rangatira {
    device    /dev/drbd1;
    disk      /dev/vgn/vm;
    address   130.209.253.129:7789;
    meta-disk internal;
  }
}
 

Cheers,

Cristian




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