Weekly Classic Computer Trivia Question (20150410)

Eric Smith spacewar at gmail.com
Sun Apr 12 02:51:43 CDT 2015

On Fri, Apr 10, 2015 at 11:03 AM, ANDY HOLT <andy.holt at tesco.net> wrote:
> d) AFAICT ZFS doesn't use the trick used by some *ix filesystems of packing the data contents for small files into the directory.
>     (to do so would clash with the reliability focus of ZFS)

That capability has recently been added to OpenZFS as the
"embedded_data" feature, so it is now available on Illumos, FreeBSD,
Linux, and OSX:

"When this feature is enabled, the contents of highly-compressible
blocks are stored in the block "pointer" itself (a misnomer in this
case, as it contains the compresseed data, rather than a pointer to
its location on disk). Thus the space of the block (one sector,
typically 512 bytes or 4KB) is saved, and no additional i/o is needed
to read and write the data block."

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