Will Synchronization Be Interrupted When Long Latency Occurs On The Links To The Two Ends Of Synchronous Remote Replication - Huawei OceanStor V3 Series Features Manual

OceanStor V3 Series
Remote Replication Feature Guide for Block
cause may be that the storage system uses the TOE interface module to connect. When the
local storage system uses the TOE interface module to connect to the remote storage system,
since protocols of the TOE and non-TOE interface modules process data in different ways, the
two systems may have different connection methods, causing connection failure.
Perform the following operations to locate and handle the problem:
1.
2.
9.15 Will Synchronization Be Interrupted When Long
Latency Occurs on the Links to the Two Ends of
Synchronous Remote Replication
Question
During synchronous remote replication, will synchronization be interrupted when the links to
the two ends encounter long latency? What's the latency threshold?
Answer
The synchronous remote replication will enter the interrupted state in this situation. At this
moment, data can be read from and written to the primary LUN, and differences between
primary and secondary LUNs are recorded. The latency threshold is 10s.
Issue 06 (2018-01-30)
NOTE
If the remote storage system uses the TOE interface module but the local storage system uses non-TOE
interface module, the above problem does not occur.
On a network where the TOE interface module connects the non-TOE interface module,
if the link fails to be created on the storage system where the TOE interface module
resides, and a communication exception error is returned, then the problem is what has
been described above. If you need to further confirm the problem, contact technical
support engineers to confirm with the system log.
After the confirmation, handle the problem with any of the following methods.
Method 1: Select the non-TOE interface module as the end for starting the connection.
The TOE interface module is the receiving end of the connection. Establish the
connection oppositely. This method helps establish the link.
Method 2: On the storage system where the non-TOE interface module resides, run the
tcp_recycle_switch.sh command to disable the function of quickly recycling
TIME_WAIT socket in the TCP connection. After the link is established, enable the
function.
a. Enter minisystem mode, run the tcp_recycle_switch.sh off command.
b. Add the remote device and establish the replication link.
c. Enter minisystem mode, run the tcp_recycle_switch.sh on command.
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