Skip site navigation (1)Skip section navigation (2)
Date:      Tue, 14 Jun 2011 09:19:32 +0200
From:      Per von Zweigbergk <pvz@itassistans.se>
To:        freebsd-fs@freebsd.org
Subject:   Disk usage and ZFS deduplication
Message-ID:  <9544F7B9-E286-4266-86E3-B4D1A667CBBD@itassistans.se>

next in thread | raw e-mail | index | archive | help
I've been following the "Impossible compression ratio on ZFS" thread =
with some interest, and it made me ask myself this:

Let us say we have a hypothetical zfs filesystem with the equally =
hypothetical files A and B. The filesystem has deduplication enabled. =
Both files have an apparent file size of 100 MB, but 50 MB of that data =
is common between the two files and thus can be deduplicated. This would =
mean that total disk usage would be 150 MB.

If you use "du" to determine disk size for a deduplication, what would =
be the result? Which file would the common data be accounted to? Or =
would it be accounted to both files somehow, in part or in full?=



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9544F7B9-E286-4266-86E3-B4D1A667CBBD>