Disparity between read/write speeds when performing SVMotion

Last night I performed a SVMotion on a VM from a SSD to a 6 disk RAID10.  The read/write rates are shown in the attached graphic.  Any idea why my read rate would be 1/2 my write rate?  It seems to me that, at the very least, they should be equal?  How can a disk write faster than the data being read?
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sbumpasAsked:
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theruckCommented:
your raid controller uses battery write cache module which is essentially a RAM which has much higher transfer rates than any SSD chips. anyway you can see that these graphs show nothing real and that vmware (and also other vendors) are just giving you something you do not need.
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sbumpasAuthor Commented:
The write cache was my first thought, but you can see in the start in the xfer the speeds are much higher - presumably while the cache is in use.  Once cache is full, the speeds bottom out (a bit) but the writes are still 2x faster.  

What do you mean the graphs "show nothing real"?
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theruckCommented:
the graphs show something but as you stated you know you can not write faster than read. at least not for such a long time. so the graph is there just to be there for marketing purposes and it is nothing you can trust. at least not the way you understand its usage.
another thing could be that it shows the data incorrectly due to some explainable reasons. like sumarising the write of all the disk spindles in the destination raid etc.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
What do you mean the graphs "show nothing real"?

if you want a longer discussion, leave the question to run for longer, for the storage Experts!
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sbumpasAuthor Commented:
I would love to know more - do I need to repost since I accepted an answer?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
You can request the Question, be "Unaccepted" if you are not happy with the solution provided.

Select Request for Assistance, under the Question Text.
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