iSCSI LUN Replication and initial copy

Question

I already have 15 Celerra iSCSI LUNs replicated and active on a single data mover. These were configured via Replication Manager and/or Celerra Manager.

I have three additinal LUNS which I am trying to replicate.

I have configured and started the replication and the status of three LUNs shows that a Full Copy is taking Place.

The first two LUNs are showing that some data is being copied although very slowly as the IP replication link bandwidth has been throttled.

The third LUN just seem to be sat there waiting.

The following is the output from the nas_replicate -info command for the third LUN.

ID                             = fs46_T3_LUN2_CK200082700003_0000_fs54_T3_LUN2_CK200071500608_012C
Name                           = gunware_tgt01_2
Source Status                  = OK
Network Status                 = OK
Destination Status             = OK
Last Sync Time                 =
Type                           = iscsiLun
Celerra Network Server         = gucelerra1
Dart Interconnect              = LON2_GU2
Peer Dart Interconnect         = GU2_LON2
Replication Role               = destination
Source Target                  = iqn.1992-05.com.emc:ck2000827000030000-3
Source LUN                     = 2
Source Data Mover              = server_2
Source Interface               = 172.20.3.73
Source Control Port            = 0
Source Current Data Port       = 61138
Destination Target             = iqn.1992-05.com.emc:ck200071500608012c-3
Destination LUN                = 2
Destination Data Mover         = server_2
Destination Interface          = 172.16.3.149
Destination Control Port       = 5085
Destination Data Port          = 8888
Max Out of Sync Time (minutes) = 10
Application Data               =
Next Transfer Size (KB)        = 0
Latest Snap on Source          =
Latest Snap on Destination     =
Current Transfer Size (KB)     = 0
Current Transfer Remain (KB)   = 0
Estimated Completion Time      =
Current Transfer is Full Copy = Yes
Current Transfer Rate (KB/s)   = 0
Current Read Rate (KB/s)       = 0
Current Write Rate (KB/s)      = 0
Previous Transfer Rate (KB/s) = 0
Previous Read Rate (KB/s)      = 0
Previous Write Rate (KB/s)     = 0
Average Transfer Rate (KB/s)   = 0
Average Read Rate (KB/s)       = 0
Average Write Rate (KB/s)      = 0

The fields highlighted contain values for my first two LUNs.

The snaps seem to have been created correctly on both Celerra's.

Does this seem correct? Is there any other command that I can run to check the current copy sessions and any other help or direction someone can give me?.

Is this the Celerra just queing the third job until one of the other two have completed? The documentation mentions 16 initial copy sessions but surely this doesn't include my active replications as that would mean I can never have more than 16 iscsi LUN replications which is not correct as Celerra's support many more replicas. Also my number is now 17 anyway with one waiting.

Thanks in advance for any suggestions.

smarti2 · Answer

An update on this issue.

I was running the nas_replicate command from the remote end and it seems I can't trust the info.

I have stopped and removed the replication that didn't seem to be working and re-created. From the source side the output shows data is actually being transfered but from target side it still shows 0's. Looks like bug but I can't find it in knowledgebase.

In additiona I have found that there is a bug in the Dart level the customer is using which means the total blocks to be transferred is always shown as 0. See below. This is very annoying as I can't see how much longer it will take to copy. Anyone have any ideas?

Impact Level Severity 1

Symptom Desc. When doing the initial full-copy on creating iSCSI
replication session from the Control Station, total blocks to be
transferred for a populated LUN was always displayed as "0".

Fix With the fix, the total number of blocks to be transferred is
displayed correctly.

Fixed in Celerra Dart Version 5.6.47.1

Doesn't seem to have a workaround or hotfix unless an EMC person on the forum knows better.

Celerra

iSCSI LUN Replication and initial copy

Was this post helpful?