[Libguestfs] [PATCH v2v] vddk: Use blocksize filter to split very large requests

[Richard W.M. Jones]

On Tue, Feb 15, 2022 at 01:43:01PM +0000, Richard W.M. Jones wrote:
> Predictably this makes no difference to the current code since nbdcopy
> is using 256K requests.  I will do some real testing when Nir pushes
> his change here:
> 
> https://listman.redhat.com/archives/libguestfs/2022-February/msg00188.html

Some test results can be found in this bug, unfortunately in private
comments.  I'll reproduce relevant excerpts below.  As you can see
this change + 8M block size approximately doubles the copying
performance and brings it roughly in line with virt-v2v 1.45.3.

https://bugzilla.redhat.com/show_bug.cgi?id=2039255


<quote>

>From mxie Comment 31:

1. Convert a guests from ESXi7.0 to rhv(rhv-upload) via vddk7.0.2 with rhv-direct=true to compare the performance between virt-v2v-1.45.98-1 and virt-v2v-1.45.3-3

v2v_version    esx7.0-vddk7.0.2-rhv-upload-rhv-direct_true                          

1.45.98-1      Convert guest: 2m19s              
               Copying disk:  8m18s        
                               
1.45.3-3       Convert guest: 2m5s        
               Copying disk:  4m28s        


>From Richard W.M. Jones Comment 32:

virt-v2v-1.45.98-1.el9.bz2039255.3:

 - Increases nbdcopy --requests to 1024

 - Increases nbdcopy --request-size to 8M

 - Introduces the blocksize filter to prevent VMware problems related to above changes:
   https://listman.redhat.com/archives/libguestfs/2022-February/msg00211.html



>From mxie Comment 33:

I think the performance has been improved by virt-v2v-1.45.98-1.el9.bz2039255.3

Test the bug with virt-v2v-1.45.98-1.el9.bz2039255.3.x86_64

Steps:
1. Convert a guests from ESXi7.0 to rhv(rhv-upload) via vddk7.0.2 with rhv-direct=true by v2v

v2v_version    esx7.0-vddk7.0.2-rhv-upload-rhv-direct_true                          

1.45.98-1      Convert guest: 2m15s              
               Copying disk:  4m54s        
                               
1.45.3-3       Convert guest: 2m5s
               Copying disk:  4m28s

</quote>

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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