RLINK has a full Replicator Log. DCM is used

H_A_N_B_U · ‎02-08-2018

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 - -

H_A_N_B_U · ‎02-08-2018

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

frankgfan · ‎02-12-2018

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

VOX

RLINK has a full Replicator Log. DCM is used