Is it possible to make rsync VMware split .vmdk's aware?

Jamie Lokier jamie at
Thu Mar 26 13:57:48 GMT 2009

Bas Bahlmann || Steady IT Systeembeheer wrote:
> Hi Matt,
> I am working a couple of days now with monolithic files and I keep
> hitting io time outs on large vmdk's while the line (IPSec tunnel) stays
> online.

I don't know if it's relevant, but rsync can be extremely slow at
transmitting large sparse files (sparse = with holes in).  The sender
scans the holes (which is very slow for many gigabytes), and might
even send zeros (I don't remember), but the receiver doesn't write
anything.  This means when there's a timeout, you have to start again
from the last non-hole in the file - this is annoying if a hole is many gigabytes long and takes hours just to transmit the hole.

The difference in size between "du" and "ls -l" will show if your vmdk
is a sparse file.

-- Jamie

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