If you are looking for a solution that allows you to replicate offsite but doesn’t cost an arm and a leg, you might want to check out the EMC VNXe line of storage arrays geared toward SMBs. In a previous blog I showed how to set up an NFS datastore. In this post, I describe how to set up a replication connection and provide guidance on what to do if you don’t have a lot of bandwidth between your two sites.

Note that if you’re trying to replicate terabytes of data over a small pipe or a site-to-site VPN, it may not work. The initial sync may never finish, and you’ll constantly be playing catchup. The good news is you can do the initial sync on the same network and then move the second (or destination) VNXe to your off-site location. So, if you have the VNXes on the same network, and you finish the initial setup, here are the steps you’d take to set up replication.

Replication connections

  1. Open Unisphere on the Source VNXe (the one staying onsite that contains your production data).
  2. Hover over the Hosts button and click Replication Connections.
  3. Follow the wizard and put in the information for your destination VNXe.

Replication setup

  1. While still in Unisphere, hover over the Storage button and select VMware (or wherever the datastore is that you’d like to replicate).
  2. Select the datastore you’d like to replicate and click the Details button.
  3. Click the Replication tab.
  4. Click the Configure Replication to a Remote System button.
  5. Follow the wizard here. You will be able to select the Destination System that you input in the Replication Connections section (Figure A).
  6. You will need to create a Storage Resource by clicking the Create Destination button. This will open a wizard on your destination VNXe. Once you complete that wizard (providing you have enough storage to accommodate the replicated datastore), you will go back and complete the wizard on the Source VNXe.
  7. You can tweak whichever settings you like once you have that setup.

Figure A

Click the image to enlarge.

Once replication has completed, you’ll need to move the destination VNXe offsite. You don’t just want to rip it out and put it in somewhere else, though.

Move the destination VNXe

  1. On your source VNXe go in and pause replication. You can do this on the Replication tab described in steps 2 and 3 of the Replication setup. Go on your destination VNXe to make sure replication is paused there, too.
  2. After the pause task has completed, go back on your destination VNXe (make sure this is the DESTINATION VNXe, because you will be shutting it down). If you shut down your source VNXe, this will bring down any production machines that are using those datastores.
  3. Hover over the Settings tab and click Service System — you’ll need the service password in order to get in. We will place both storage processors in Service Mode before we shut down the VNXe.
  4. Find the non-primary storage processor. You can tell which one is the primary by clicking both of them and seeing what it says in the details (Figure B).
  5. Click the non-primary storage processor, highlight Enter Service Mode in the right pane, and click the Execute Service Action button. This will take several minutes. When it reboots, you will see that it says Service Mode next to Mode in the details pane (Figure B).
  6. When the non-primary storage processor has completed this task, do the same thing with the primary storage processor. Make sure you wait until it also has Service Mode listed next to Mode.
  7. Pull the power cables from the back of the VNXe.
  8. Unrack the VNXe and transport it to the off-site location.
  9. Once in the new location, racked, plug everything back in.
  10. If you’re using the same address scheme at your off-site location, you can pull up Unisphere using the same IP address and skip ahead to step 16.  If you’re using a different address scheme, you need to go to the next step.
  11. Connect a computer to the same network as the VNXe (preferably the same subnet).
  12. Download the Connection Utility from EMC (you will need an EMC PowerLink account for this).
  13. Pull up the Connection Utility and click Discover to find the VNXe.
  14. Once you find the VNXe, click Next and you will be able to enter a new IP address, subnet mask, and gateway. This will take about 10 minutes after you apply the changes.
  15. Open Unisphere by connecting to the new IP address.
  16. Unisphere will be in Service Mode because the primary Storage Processor (SP) is in Service Mode; so, you won’t be able to configure anything until you go back into Settings | Service System and reboot the SPs. This will take several minutes for each SP.  This will put them back in Normal mode, and you can continue configuration.
  17. Hover over the Settings button and choose Shared Folder Servers (for NFS) or iSCSI Server Settings (for iSCSI).
  18. Change the NFS or iSCSI server IP settings to match your current IP scheme (you can skip this step if your IP addresses didn’t change from site to site).
  19. Hover over System and choose System Replications.
  20. Select the replication you paused and re-enable it. When it starts working again, you now have off-site replication.

Figure B

Click the image to enlarge.

Since you’ve already completed the initial sync, you only need to replicate changes to the production storage. Your given bandwidth will most likely be able to handle this unless you’re changing all of your data all of the time (which is somewhat rare).

Keep in mind, you don’t have to do the initial replication at the same site; in fact, it’s a lot easier if you don’t have to move it after initial configuration. However, that might not be an option if you have too much data.

If you have any questions or comments, please feel free to leave them below.