ADE Global replication seeding

Objective:

When implementing replication over slow links or recovering replication after a long outage the initial synchronization or re-synchronization can be very time consuming and impact overall performance of the deduplication solution.

By seeding we put in place the data on the secondary server using alternative transport mechanisms to pre-load it before we start replication since the data is already there the synchronization will be a lot faster as no data needs to be transferred.

Limitations:

Seeding is only possible for simple A->B replication

The ADE components must be in the same (identical pathnames) location on source and destination

Moving the data needs to be done OFF-LINE hence the seeding will require downtime.

The procedure requires editing critical configuration items that can make the Deduplication solution unusable and potentially lead to data-loss, the engagement of an Atempo Consultant is highly recommended.

Preparation:

On the Source server:

Run the ade_admin command  bck_list  and record the output

Typically this will be similar to what is shown below

HOME=/Atempo/AtempoDedupEngine/myAdeInstallDirectory

DB_CORE=/Database/CoreDB

DB_LOG=/Database/CoreDB/syslog

STAT=/ADE_Blocs01/Blocks

BLOCKS=/ADE_Blocs02/Blocks

BLOCKS=/ADE_Blocs03/Blocks

STREAM=/HSS/Streams * if HSS is enabled

ALN=/AtempoDedupEngine/default/ALN_HVDS  * if ALN or HVDS is enabled

If the destination is already installed and replication has been used

Using ade_admin  perform an del_all_repli  is required to remove the current replication relationship

Using ade_admin  disable the garbage collector and compactor

Hence    ade_admin service disable 7 and service disable 9

Now you should shutdown the source server

On the destination server:

If ADE is already installed :

Use ade_admin  info command to collect the  Server UUID of the installation

Output from the info command will be similar to :

ESC-HSS:23232> info

Server version                    : 4.0.3.24252  (started 3 days, 21 hours and 20 minutes ago)

Server UUID                       : 82367175-2d39-8c42-b25c-7befa3175465

Hostname                          : ESC-HSS:23232

Verify that the ade_admin bck_list command shows the same output than what has been seen on the source server if this is not the case you will need to perform an un-install / install of the destination server software.

Copy the data :

With both ADE services down copy/transfer the contents of the paths listed by the bck_list command to the destination server overwriting the current content.

This will result in the destination server to be a CLONE of the source so make sure the source is offline when bringing up the destination.

Change the uuid on the destination

If you have a previous uuid use the ade_admin  change_uuid  command

If you have a new installation use the ade_admin renew_uuid command

This will stop the service and change its identity

Re-establish replication:

Make sure both source and destination are up and running.

Use ade_admin or the GUI to re-establish the replication

Expl: ade_admin  add_repli destination:port

Post seeding :

After both servers got in sync (allow for 24h) you should re-enable the garbage collector and compactor using ade_admin service enable 7 and service enable 9.