Challenge
Some machines that should be replicated to set up migration or disaster recovery process exceed the capabilities of customer's network connection in terms of machine size / network bandwidth. Completing initial replication of a 50Tb machine might take weeks on 100Mbit/s channel with a possibility of networking failures/outages during this process.
Solution
To overcome this challenge, Hystax Windows Replication Agent (HWRAgent) can perform replication of selected volumes onto the local storage (Direct Attached Storage, DAS) instead of sending the data to the cloud via external network. With the help of DAS, initial replication can be performed by sending data from system volumes to the cloud while keeping replicas of data volumes on DAS. The replicated machine can subsequently be spun up in the target cloud just after the initial replication without the necessity to check data volumes or adjust failover/migration settings. The data from DAS can be transferred to the cloud by physically attaching it to a Hystax instance in the target cloud or by uploading it separately from a different location with a better network connection.
Workflow description
1. Install HWRAgent on the machine to be replicated.
2. Identify volumes that need to be transferred to DAS
3. Attach DAS to the machine. It can be a local disk or a local network location. Make sure that DAS has enough storage space to store the replicated data - its available storage should not be less than sum of volumes to be placed on DAS.
4. Follow the HWRAgent configuration flow described in the section below.
5. Start replicating the machine. Wait for the completion.
6. Ensure that replica files are safely stored on DAS.
7. Contact Hystax support in order to transfer DAS data to the cloud.
HWRAgent configuration for DAS
1. Stop the HWRAgent service.
2. Open windows command console (cmd.exe) and use the command “mountvol” to get information about volumes in your machine. Identify those needed to be placed on DAS.
3. Run Notepad as Administrator and open the config file “C:\ProgramData\Hystax\acura\cbt.xml”.
Add the following section containing information about the volumes which need to be replicated onto DAS:
<DasVolumes>
<Volume>\\?\Volume{af654a91-b197-42b3-9660-dd84352be415}\</Volume>
<Volume>\\?\Volume{7f7484a8-cfd9-4871-9abf-81619805907f}\</Volume>
</DasVolumes>
R
eplace volume paths with the paths to your volumes.
4. Add the following section to set a path to DAS output directory:
<DasPath>\\fileserver\Downloads\DAS</DasPath>
5. If DAS is a local disk, exclude it from the replication:
<ExcludedVolumes>
<Volume>\\?\Volume{b0db1f46-d3bd-4c27-8d08-165236e1bed6}\</Volume>
</ExcludedVolumes>
6. Save the config file.
7. Start/restart the HWRagent service to apply the changed config file.
8. Run replication, wait for its completion.
9. As theresult, you will see the replicated machine in the Synced/Protected state in Hystax Control Panel and a set of .map and .bin files in DasPath directory.
You will be able to return to regular incremental replications via network once your DAS
data is ingested into the cloud. To do that, stop the HWRAgent console application, remove all DAS-related settings from cbt.xml and start the HWRAgent service.