Replicating continuously

[rfn]

Hi,

I'm in the process of configuring Veaam Backup v5 and is trying out the replication feature to see if it's a better solution than using EqualLogic replication. Veeam Backup has the option to backup and replicate "continuously", which would mean that data is replicated as soon as possible.

Wouldn't this keep a live snapshot constantly on the datastore, or force a lot of create/remove snaphot operations? Won't that hurt datastore performance a lot to have snapshots on there all the time for alle VM's? I'm no expert but have read a lot about some locking that occurs whenever as snapshot is present on a VM on a datastore.

[Gostev]

Hello, that is correct - this will result in a lot of create/remove snaphot operations, and so this mode should be used wisely. Every snapshot operation puts additional load on datastore. However, many SAN (for example, Dell Equallogic with the 5.0.2 firmware) now implement VAAI (search this forum) that essentially enables hardware-assisted snapshots and locking. As a result, these activities are offloaded from ESX to the storage array, potentially making such continuous replication a very real possibility for certain types of workloads.

[ctchang]

I woud like to add more to this.

An updated review from InfoWorld about New EqualLogic firmware takes a load off VMware
http://www.infoworld.com/print/140856

Another VMware-only feature in version 5 is hardware-assisted locking. Normally, when VMware conducts certain operations -- such as powering a virtual machine on or off, executing a VMotion, creating a new virtual machine, or deleting a snapshot -- the entire VMFS file system is locked momentarily. When these actions occur sporadically, it's not much of a problem, but when there's a run on the VMware farm -- such as when a bunch of new VDI desktops are powered on -- it can create delays. In this new firmware version, EqualLogic arrays can lock only the blocks required to perform that operation, allowing the VMFS file system to continue to serve other requests. Thus, there are no delays felt by concurrent operations, which can help significantly when the file system is getting hammered.

That's why, but still don't over use it.

I've also written a summary about Veeam Backup & Replication v5 and ESX VAAI with Equallogic Array in my blog.
http://www.modelcar.hk/?p=2912

Enjoy.

[matthieu178]

[merged]

Hi Guys,

Still having some ressearch done about veeam utilisation.
I'm wondering in which case it is good to have continous backup/replication?

In my opinion you should have good storage i/o's behind.

In my case I have to physical esxi servers without shared storage, eveything goes over copper link.
I guess it is not best practise to put continous replication in this case.

Would it result in performance issues?

Thanks a lot for your answers.

[matthieu178]

Thanks a lot for these answer
It'll help me justify the fact it's not best practise

[TrevorBell]

Equallogic F/W 5.1 is now released with further enhancements for vmware.

read @ www.equallogic.com