RLINK has a full Replicator Log. DCM is used

Hi Guys,

I need help on my replication issue. We just move the server on the other site after the replication had finished. I paused the replication before moving the hardware. After I resumed and resynchronized the RLINK, data volumes used DCM instead of SRL. Please see below commands and attached images.

I'm using InfoScale Enterprise 7.0.1 running on Windows 2008 Server R2.

1. Primary (SVR1)

vxrlink -g <diskgroup> status <RLINK>

RLINK has a full Replicator Log. 13% (1234567891) DCM is used.

C:\Users\administrator>vxprint -VPl
 
Diskgroup = BasicGroup
 
Diskgroup = fileshare_dg
 
Rvg        : fileshare_rvg
state      : state=ACTIVE kernel=ENABLED
assoc      : datavols=G:,F:
             srl=\Device\HarddiskDmVolumes\fileshare_dg\rvgvol
             rlinks=HQ_RLINK
att        : rlinks=HQ_RLINK
checkpoint :
flags      : primary enabled attached dcm_logging resync_started clustered
 
Rlink      : HQ_RLINK
info       : timeout=78 packet_size=1400
             latency_high_mark=10000 latency_low_mark=9950
             bandwidth_limit=none
state      : state=ACTIVE
             synchronous=override latencyprot=off srlprot=autodcm
assoc      : rvg=fileshare_rvg
             remote_host=192.168.0.222
             remote_dg=fileshare_dg
             remote_rlink=DR_RLINK
             local_host=192.168.0.229
protocol   : UDP/IP
flags      : write attached inconsistent cant_sync connected dcm_logging resync_started

 

C:\Users\administrator\>vxprint
 
Diskgroup = BasicGroup
TY NAME         ASSOC        KSTATE   LENGTH(S)   PLOFFS   STATE    TUTIL0  PUTIL0
 
Diskgroup = fileshare_dg
TY NAME         ASSOC        KSTATE   LENGTH(S)   PLOFFS   STATE    TUTIL0  PUTIL0
sd Disk1-01     Volume1-01   ENABLED  30064506880 0        -        -       -
sd Disk2-01     Volume1-01   ENABLED  2192782131 30064506880        -        -       -
sd Disk2-02     Volume2-01   ENABLED  25724241920 0        -        -       -
sd Disk3-01     rvgvol-01    ENABLED  41943040 0        -        -       -
sd Disk3-02     Volume1-02   ENABLED  512      0        -        -       -
sd Disk3-03     Volume2-02   ENABLED  512      0        -        -       -
sd Disk3-04     rvgvol-01    ENABLED  41943040 41943040        -        -       -
dm Harddisk1    Disk1        -        30064510909-        -        -       -
dm Harddisk2    Disk2        -        27917029309-        -        -       -
dm Harddisk3    Disk3        -        104615869-        -        -       -
v  Volume1      -            ENABLED  32257289011-        ACTIVE   -       -
pl Volume1-01   Volume1      ENABLED  32257289011 -        ACTIVE   -       -
pl Volume1-02   Volume1      ENABLED  512      -        ACTIVE   -       -
v  Volume2      -            ENABLED  25724241920-        ACTIVE   -       -
pl Volume2-01   Volume2      ENABLED  25724241920 -        ACTIVE   -       -
pl Volume2-02   Volume2      ENABLED  512      -        ACTIVE   -       -
dg fileshare_dg fileshare_dg     -        -        -        -        -       -
rv fileshare_rvg -            -        -        -        ACTIVE   -       -
rl HQ_RLINK fileshare_rvg -        -        -        ACTIVE   -       -
v  rvgvol       -            ENABLED  83886080 -        ACTIVE   -       -
pl rvgvol-01    rvgvol       ENABLED  83886080 -        ACTIVE   -       -

 

2. Secondary (SVR2)

C:\Users\Administrator>vxprint -VPl
 
Diskgroup = BasicGroup
 
Diskgroup = fileshare_dg
 
Rvg        : fileshare_rvg
state      : state=ACTIVE kernel=ENABLED
assoc      : datavols=\Device\HarddiskDmVolumes\fileshare_dg\Volume1,\Device\HarddiskDmVolumes\fileshare_dg\Volume2
             srl=\Device\HarddiskDmVolumes\fileshare_dg\rvgvol
             rlinks=DR_RLINK
att        : rlinks=DR_RLINK
checkpoint :
flags      : secondary enabled attached clustered
 
Rlink      : DR_RLINK
info       : timeout=0 packet_size=1400
             latency_high_mark=10000 latency_low_mark=9950
             bandwidth_limit=none
state      : state=ACTIVE
             synchronous=override latencyprot=off srlprot=autodcm
assoc      : rvg=fileshare_rvg
             remote_host=192.168.0.229
             remote_dg=fileshare_dg
             remote_rlink=HQ_RLINK
             local_host=192.168.0.222
protocol   : UDP/IP
flags      : write attached inconsistent cant_sync connected
 
C:\Users\Administrator>vxprint
 
Diskgroup = BasicGroup
TY NAME         ASSOC        KSTATE   LENGTH(S)   PLOFFS   STATE    TUTIL0  PUTIL0
 
Diskgroup = fileshare_dg
TY NAME         ASSOC        KSTATE   LENGTH(S)   PLOFFS   STATE    TUTIL0  PUTIL0
sd Disk1-01     Volume2-01   ENABLED  25724241920 0        -        -       -
sd Disk1-02     Volume1-01   ENABLED  45295616 32211993395        -        -       -
sd Disk2-01     Volume1-01   ENABLED  32211988480 0        -        -       -
sd Disk3-01     rvgvol-01    ENABLED  83886080 0        -        -       -
sd Disk3-02     Volume1-01   ENABLED  4915     32211988480        -        -       -
sd Disk3-03     Volume2-02   ENABLED  512      0        -        -       -
sd Disk3-04     Volume1-02   ENABLED  512      0        -        -       -
dm Harddisk1    Disk3        -        104595389-        -        -       -
dm Harddisk2    Disk2        -        32211992509-        -        -       -
dm Harddisk3    Disk1        -        25769541565-        -        -       -
v  Volume1      -            ENABLED  32257289011-        ACTIVE   -       -
pl Volume1-01   Volume1      ENABLED  32257289011 -        ACTIVE   -       -
pl Volume1-02   Volume1      ENABLED  512      -        ACTIVE   -       -
v  Volume2      -            ENABLED  25724241920-        ACTIVE   -       -
pl Volume2-01   Volume2      ENABLED  25724241920 -        ACTIVE   -       -
pl Volume2-02   Volume2      ENABLED  512      -        ACTIVE   -       -
dg fileshare_dg fileshare_dg     -        -        -        -        -       -
rv fileshare_rvg -            -        -        -        ACTIVE   -       -
rl DR_RLINK fileshare_rvg -        -        -        ACTIVE   -       -
v  rvgvol       -            ENABLED  83886080 -        ACTIVE   -       -
pl rvgvol-01    rvgvol       ENABLED  83886080 -        ACTIVE   -       -
 
 
2 Replies

Re: RLINK has a full Replicator Log. DCM is used

Hi Guys,

 

Just called the Veritas support. We just changed the protocol from UDP/IP to TCP/IP on the VEA consoole.

DCM is now draining.

Thanks

Paul

Highlighted

Re: RLINK has a full Replicator Log. DCM is used

Hello Paul,

 

The way to reply DCM log is to run the command below

 

vradmin -g <dg_name> resync >rvg_name>

resync     Starts replay an active DCM in the Replicated Data Set (RDS) rvg.
    The resync command starts replay of a DCM that is active due to SRL overflow or failback logging. Replay occurs for all RLINKs on which the dcm_logging flag is set. If any of these RLINKs are disconnected or paused, resynchronization is delayed until this condition clears. Detaching a disconnected or paused RLINK clears the dcm_logging flag, and allows resynchronization to proceed on any remaining RLINKs.


    The resync keyword can optionally be used with the cache or cachesize attributes to to create a space-optimized snapshot of the secondary data volumes before starting the resynchronization process.

 

vvr protocol

VVR exchanges two types of messages between the Primary and the Secondary: heartbeat messages and data messages. The heartbeat messages are transmitted using the UDP transport protocol. VVR can use either the TCP transport protocol or the UDP transport protocol to exchange data messages.

The choice of protocol to use for the data messages is based on the network characteristics. TCP has been found to perform better than UDP on networks that lose packets. However, you must experiment with both protocols to determine the one that performs better in your network environment.

When using the TCP protocol, VVR creates multiple connections, if required, to use the available bandwidth. This is especially useful if there are many out of order packets.

Note:   

You must specify the same protocol for the Primary and Secondary; otherwise, the nodes cannot communicate and the RLINKs do not connect. This also applies to all nodes in a cluster environment.

VVR uses the UDP transport protocol by default. For information on how to set the network protocol,

 

General peaking, if your VVR goes to DCM mode on a regular basis, you need to review your network bandwidth, application data bandwidth and the size of SRL.  If the application keeps generating new data in a rate much higher than the data replication bandwidth and the SRL is now big enough, you will see frequently replication witched to DCM logging or overflow.

 

Regards,

 

Frank