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ysfpatrick1
Contributor
Contributor

Take too long time on "initial full sync"

I try to use VR 5.5 to replicate a testing VM which has a 8GB disk with 2GB data only (vmdk file size is 2.02GB only).  I have copy all the VM file to the DR site for initial full sync. However I still need around 10min to complete the initial full sync with 14.63MB of delta sync only. 

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I think this is not bandwidth issue, as not much data is transferred to DR site. I think most of time used on calculate the delta change. Would you please tell me how to reduce the time used for  initial full sync?
As I have a production VM with around 1TB data need for DR. And may need around 3 days to complete the initial full sync. Thanks

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memaad
Virtuoso
Virtuoso

Hello,

Even if you have transferred the whole virtual machine file on DR site, use that as seed, it will do initial sync after comparing data difference between the source and DR site virtual machine files. And then it will replicate only changed block.

This might help you Advanced vSphere Replication Options for Single VM Replication Performance | VMware vSphere Blog - V...

Mohammed | Mark it as helpful or correct if my suggestion is useful.
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kwerneburg
VMware Employee
VMware Employee

Those settings I outlined in the blog are only good for 5.0/5.1.  In 5.5 they won't do much of anything as there were some fairly fundamental changes to the way changed blocks are loaded into a memory heap and buffered.  1 TB is a huge disk to do calculation on every block and compare...

Pretty much the only option with 5.5 is to wait out the calculation and comparison of blocks.  Improving performance of initial sync is a big area of focus though...

The calculation of block changes is distributed among the hosts on the clusters though - any chance the CPUs are bottlenecked on the recovery site?

| @vmKen | VMware Technical Marketing |
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