1. Copyright © 2014 EMC Corporation. All Rights Reserved.
The system switches to three-phase distribution mode (also called fast-forwarding):
1. When there are performance issues with either the copy or journal storage.
2. When the journal lag exceeds the Maximum Journal Lag
When does three-phase distribution end?
If the system entered three-phase distribution mode because of performance issues with either the copy volumes or the
copy journal, the system resumes five-phase distribution after a short period of time.
If the system entered three-phase distribution mode because the journal lag exceeded the Maximum Journal Lag setting,
the system resumes five-phase distribution as soon as the actual journal lag falls below the value of the Maximum
Journal Lag setting in the “Journal policies” (p 152) according to the “Maximum journal lag example” (p 81).
The Maximum Journal Lag is the maximum amount of snapshot data (in MB, or GB) that is permissible to retain in the
copy journal before distribution to the copy storage. In other words, the amount of data that would have to be distributed
to the copy storage before failover to the latest image could take place, or (in terms of RTO) the maximum time that
would be required in order to bring the copy up-to-date with production.
When the Maximum Journal Lag value is exceeded, in order to accelerate the distribution process, the system starts
clearing out all snapshots irrelevant to the data that would have to be distributed to the copy storage before failover to the
latest image could take place, to ensure the RTO policy.
Lets say production has made writes up to the present point-in-time (Now), and all of the snapshots in the copy journal up
until point-in-time T1 are waiting for distribution, after which all snapshots have already been distributed to the copy
storage (up until point-in-time T0), so the total journal lag (the maximum time that would be required in order to bring the
copy up-to-date with production) is between point-in-time T1 and Now (or Now > T2 > T1), where point-in-time T1
represents the state of data at the copy storage Now.
Now let’s say that a Maximum Journal Lag policy of 1GB has been set by the user in the “Journal policies” (p 152) and

2. Copyright © 2014 EMC Corporation. All Rights Reserved.
The following is an example of a CRR set-up.
We will first look at the source (production side) – we see 5 Recoverpoint (ORS)
sessions for devices 0111, 0113, 0116, 014D, 0152. These are all showing as
fully synchronized.

3. Copyright © 2014 EMC Corporation. All Rights Reserved.
8F,SANC,SHOW,SESS

4. Copyright © 2014 EMC Corporation. All Rights Reserved.
When a consistency group is enabled, an Open Replicator RecoverPoint session
is created for each production volume within that consistency group.
8F,SANC,SHOW,SESS,,’device’ will give more information on a particular RP
session.

5. Copyright © 2014 EMC Corporation. All Rights Reserved.
We can use symaccess commands to check storage groups etc – note the
naming structure will usually have ‘RPA’ for the RP storage provisioning.

6. Copyright © 2014 EMC Corporation. All Rights Reserved.
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7. Copyright © 2014 EMC Corporation. All Rights Reserved.
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