Stuart Anderson wrote:
> On Tue, Apr 15, 2008 at 03:51:17PM -0700, Richard Elling wrote:
>
>> UTSL. compressratio is the ratio of uncompressed bytes to compressed bytes.
>> http://cvs.opensolaris.org/source/search?q=ZFS_PROP_COMPRESSRATIO&defs=&refs=&path=zfs&hist=&project=%2Fonnv
>>
>> IMHO, you will (almost) never get the same number looking at bytes as you
>> get from counting blocks.
>>
>
> If I can't use /bin/ls to get an accurate measure of the number of compressed
> blocks used (-s) and the original number of uncompressed bytes (-l). What is
> a more accurate way to measure these?
>
ls -s should give the proper number of blocks used.
ls -l should give the proper file length.
Do not assume that compressed data in a block consumes the whole block.
> As a gedankan experiment, what command(s) can I run to examine a compressed
> ZFS filesystem and determine how much space it will require to replicate
> to an uncompressed ZFS filesystem? I can add up the file sizes, e.g.,
> /bin/ls -lR | grep ^- | nawk '{SUM+=$5}END{print SUM}'
> but I would have thought there was a more efficient way using the already
> aggregated filesystem metadata via "/bin/df" or "zfs list" and the
> compressratio.
>
IMHO, this is a by-product of the dynamic nature of ZFS.
Personally, I'd estimate using du rather than ls.
-- richard
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