In an earlier and very popular article I compared SRM replication options: “VMware SRM: vSphere Replication vs. Array Based Replication“. In this article I want to broaden the scope and add three other Disaster Recovery (DR) options for virtualized environments; namely the ‘free’ vSphere Replication option, Veeam Backup & Replication and Zerto.
Both Veeam and Zerto offer a virtual machine level, hypervisor based replication/DR solution. In the case of Veeam the replication option is part of their core backup application. Zerto is 100% DR solution and offers some very interesting advanced features. vSphere Replication is included in vSphere since version 5.1 offering some limited replication options.
For this comparison I will use the same kind of table as in the previous article, adding some columns:
- VR = vSphere Replication included in your vSphere license.
- SRM/VR = Site Recovery Manager using VMware vSphere Replication.
- SRM/ABR = Site Recovery Manager using Array Based Replication.
- Veeam B&R = Veeam Backup & Replication version 6.5, replication is part of this solution.
- Zerto = Is Zerto’s Business Continuity/Disaster Recovery solution for Enterprise. There’s is also a version for Cloud Providers available.
The table doesn’t include the vSphere Metro Storage Cluster (vMSC) solution. With vMSC you’re building one vSphere datacenter on top of a streched storage solution like NetApp Metrocluster, EMC vPlex or HP Lefthand. This is a different approach compared to solutions discussed in this article.
Disaster Recovery Comparison
|Replication type||vSphere layer, using virtual appliances||vSphere layer, using virtual appliances||Array based replication (e.g. snapmirror, truecopy)||vSphere layer, using Veeam Backup & Replication application||vSphere layer, using virtual appliances. A VA is deployed on each host|
|Licensing||VR is included in vSphere||VR is included in vSphere, SRM licensed per VM||Replication license required, costs depend on storage vendor. SRM licensed per VM.||Licensed as part of Veeam Backup & Replication, license per socket.||Zerto is licensed per VM.|
|Uniform storage infrastructure required||No, replication is VM based||No, replication is VM based||Yes, same vendor and sometimes same model||No, replication is VM based||No, replication is VM based|
|Replicate local storage||Yes||Yes||No||Yes||Yes|
|Replicate physical servers||No||No||Yes||No||No|
|Replication Granularity||Per VM||Per VM||Per LUN and/or Consistency Group||Per VM||Per VM and/or per VM group|
|Configure Consistency Group||No||No||Yes (Depending on the storage vendor)||No||Yes (Virtual Protection Groups)|
|Recovery Points||Just one, latest succesful replication date||Just one, latest succesful replication date. (SRM 5.5 allows to revert to 24 points in time)||Just one for SRM, although you can of course create snapshots on the storage level. SRM isn’t snapshot aware.||28 points in time||Up to 5 days earlier|
|Management (how)||vSphere Web Client plugin||vSphere Web Client plugin||Storage vendor management interface. Sometimes plugins are available.||Veeam B&R management console. V7 introduces a vSphere Web Client plugin.||vSphere Web Client plugin|
|Management (who)||vSphere administrator||vSphere administrator||Storage administrator||Veeam administrator||Zerto administrator|
|RPO||RPO of 15 minutes – 24 hours||RPO of 15 minutes – 24 hours||RPO of 0 minutes with synchronous replication||Based on a replication schedule which can be set to continuously||RPO of seconds|
|Application consistency||Yes, using VSS||Yes, using VSS||No, VMs/data is in crash consistent state||Yes, using VSS||Yes, using VSS|
|Orchestration||No, although vSphere offers various scripting options e.g. through PowerCLI||Yes, SRM is all about DR orchestration||Yes, SRM is all about DR orchestration||No, but with the Veeam B&R Powershell plugin you can write an orchestration script||Yes, you can configure startup order for a Virtual Protection Group. Zerto includes scripting options which will give additional automation options.|
|Raw Device Mappings||Not supported||Not supported||Supported||Not supported||Virtual and physical RDMs are both supported.|
|Fault Tolerance VMs||Not supported||Not supported||Supported||Not supported||Not supported|
|Replicate Clusterd VMs||No||No||Yes||No||No|
|VMware vCloud (Director) Integrated||No (you can replicate VMs, but vCD is not aware of any replication options)||No (you can replicate VMs, but vCD is not aware of any replication options)||No (you can replicate LUNs hosting VMs, but vCD is not aware of any replication options)||No, but there are some improvements in Veeam B&R version 7, to be available soon.||Yes, Zerto for Cloud Providers is available. The provider must have Zerto installed.|
Although good old Array Based Replication is still a good option, virtual DR options offer some nice advantages: per VM granularity, application consistent VMs and no need to have an identical storage solution at both sites. In the case of Zerto they even integrate with vCloud Director, which makes this solution also a good option for (vCloud based) IAAS providers.
More information on the respective products:
- vSphere Replication information is here.
- Information about Site Recovery Manager with vSphere Repication and/or Array Based Replication, here.
- Veeam Backup & Replication version 6.5 information is here, more info on version 7 here. An evaluation and a free version (offering limited functionality) is available for download.
- Zerto information is here, Zerto offers a trial version of their product.