Now that I’ve given you a quick overview of the architecture of Coho SiteProtect, I’d like to provide you with the basics for implementing SiteProtect in your data center. This is the 2nd in my series of posts on our site-to-site replication offering. As I discover the best practices for deploying SiteProtect in various infrastructures and scenarios, I’ll document those here as well, so stay tuned for those…
Without further ado, here is the step-by-step set-up procedure for SiteProtect…
Pairing the Sites
The first step in setting up remote replication is establishing a trusted relationship from the local site to the remote site. This is done from the Settings > Replication page in the Coho web UI, indicated by the gear (settings) icon (Figure 1).
Figure 1: Settings > Replication page
From here, click the “Begin replication setup” link which brings you to the configuration screen for the local site (Figure 2).
Figure 2: Settings > Replication > Local Site page
Here, you’ll specify the network settings for the site to site communication. It is worth noting that the replication traffic is sent on a VLAN to simplify network management for enterprise environments.
Here you can also configure bandwidth throttling for outbound traffic in case you need to limit the usage of the site to site interconnect. The same can be done on the remote site which means that both incoming and outgoing throughput can be controlled. Bear in mind that by limiting the traffic, you may increase the time it takes for a workload to finish replicating, in other words, increase the RPO.
Once that’s complete, you’ll click “Next” and specify the IP and password of the remote DataStream. Click “Next” again to proceed (Figure 3).
Figure 3: Settings > Replication > Remote Credentials page
Once the wizard confirms a connection to the other side, you’ll specify the remote system’s VLAN, replication IP address, and netmask, as well as the default gateway for the other side and click “Next” (Figure 4).
Note: On this page the bandwidth limit relates to outbound traffic from the remote site; or put another way, the inbound replication traffic arriving at the local site.
Figure 4: Settings > Replication > Remote Network page
Finally, you’re brought to step 4, which is the “Summary” page and allows you to review the configuration before applying the settings. Click “Apply and Connect” to complete the wizard (Figure 5).
Figure 5: Settings > Replication > Summary page
From this point forward, you’ll be presented with the following view when you go to the Settings > Replication page. You can see here (Figure 6), the IP of the remote node and that replication is active.
Figure 6: Settings > Replication page (completed)
Configuring Workloads and Schedules
Now that the initial pairing is complete, you’ll visit the “Snapshots and Replication” page to customize which workloads are replicated as well as the snapshot & replication interval for each (Figure 7).
Figure 7: Snapshots / Replication > Overview page
Here (Figure 7), we provide an overview of the workloads. This is a dashboard which tells us the number of VMs with snapshots as well as replicated snapshots. For all of a site’s workloads to be protected, they should all have replicated snapshots, ensuring that any of those workloads can be recovered on the remote site in the event of a disaster.
We also provide a summary of the workloads covered by replication, how many bytes have been transferred as well as the average replication time. These statistics provide the assurance that replication is functional, and also the rate of change of the data, allowing you to determine if your replication interval is appropriate for the bandwidth you have available. If your average replication time is greater than your snapshot schedule, you can modify it accordingly.
To configure or modify workloads, proceed to the “Workloads” page (Figure 8).
Figure 8: Snapshots and Replication > Workloads page
Here (Figure 8), we denote the local vs. the remote workloads, provide a record of when the last snapshot was taken, and display the assigned schedule.
Note: VMs which have been deleted are denoted with a strike through the name.
Under “Snapshot Record”, you can click on the calendar icon to view snapshot date, name and description, as well as the status of replication. In this example, we have recently enabled the workload for replication denoted by the word “Scheduled” (Figure 9).
Figure 9: Snapshots and Replication > Workloads > Snapshot Record page
To manually protect a specific workload, click the camera icon next to that workload. This will allow you to take a manual snapshot and replicate that snapshot (Figure 10).
Figure 10: Snapshots and Replication > Workloads > Snapshot page
Most users will want to protect a number of VMs at once. The best way to do this is from the “Default Schedule” page (Figure 11).
Figure 11: Snapshots and Replication > Default Schedule page
In this example we have selected a RPO of 15 minutes by replicating the snapshot every 15 minutes. The frequency of snapshots is best determined by the needs of the application and the automated snapshot schedule for Coho offers flexibility, from minutes to months.
Note: Quiescing snapshots puts the system in a state that maintains application consistency before taking the snapshot, however this is only available in the daily and weekly schedule. Taking quiesced snapshots more frequently may cause significant performance penalties. These performance penalties are not related to the Coho storage but to how snapshots are executed within the VMware environment. A crash consistent snapshot (no quiesce) can be done very frequently on the Coho storage without performance penalty.
In the event of a disaster you’ll want to be be able to bring up your applications in the remote site. This is done from the “Failover/Failback” view (Figure 12).
Figure 12: Snapshots and Replication > Failover/Failback page
Initially, failover and failback are disabled in order to protect you from instantiating multiple copies of the same VM. You make the decision (from either location) to put the disaster recovery plan in-motion. If you’re ready to proceed, click the “Enable” button to enable failover (Figure 13).
Figure 13: Snapshots and Replication > Failover/Failback page (enabled)
You can now go to the remote DataStream and clone your replicated workloads to the remote system. Open up the web UI of the remote DataStream and, again, go to the Snapshots and Replication > Workloads page (Figure 14).
Figure 14: Snapshots and Replication > Workloads page (remote)
Click the “Remote Workloads” checkbox to filter by those workloads. These are the workloads available for failover from the primary to the disaster site. Choose the workload by clicking the calendar icon. Browse the recent snapshots and choose one to clone from, by clicking the clone icon (Figure 15).
Figure 15: Snapshots and Replication > Workloads page (failover)
Once you’ve selected the desired snapshot, enter a VM name and choose a target vSphere host. Click “Clone” to clone it and recover it to the destination site. The workload is now failed-over to continue serving data to your users. Just power it on in vCenter and you’re ready to go.
If at some point, the primary site comes back online, we support failing workloads back to their original location. This is done from the Snapshots and Replication page. On the workload that you’d like to failback (Figure 16), click the calendar icon to view the available snapshots, then click the red arrow to sync the snapshot to the original VM. Once the VM is powered on, your app will be back in the original location with all of the changed data from snaphots replicated from the remote site since the failure occurred; simple and easy just like it should be.
Figure 16: Snapshots and Replication > Workloads page (failback)
Well, that’s it for the initial implementation. As you can see, Coho SiteProtect is easy to get set-up and configured in any environment. Next, we’ll dive into some of the best practices of how to configure SiteProtect for optimal performance for environments of various sizes and requirements.
Until then, if you’d like more info about Coho SiteProtect, click here!
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