Sanity check: iotop actual vs total disk reads

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gigatexal

I'm here to learn
Nov 25, 2012
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Portland, Oregon
alexandarnarayan.com
I think I know the answer here just would like to confirm with the internet ether:

using a ZFS datastor with compression and you do a read against a file that is highly compressed (disk image of 700G but only half of it is data i.e it came from dd if=/dev/hda of=img.raw ...) total disk read is what it would have read in MB if it were uncompressed but actual is the actual disk read in that it read 10MB and then uncompressed it to say 30MB on the fly?