zfs discuss - Oct 2009 - resolve zfs properties "default" to actual value

Hi,

how can I find out what the actual value when the default applies to a zfs
property?
# zfs get checksum mpool
NAME PROPERTY VALUE SOURCE
mpool checksum on default

(In this particular case I know what the value is, either fletcher2 or fletcher4
depending on the build)
But how can one find out in general what the actual value is? For any property.

thank you,

Frederik
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This message posted from opensolaris.org

Hi Frederik,

In most cases, you can use the zfs get syntax below or you can use the
zfs get all fs-name to review all current property settings.

The checksum property is a bit different in that you need to review
the zfs.1m man page checksum property description to determine the value 
of the default checksum property.

You can use other methods to determine the current checksum value,
but no easy way exists.

The property descriptions and their defaults are up-to-date in
table 6-1, here:

http://docs.sun.com/app/docs/doc/817-2271/gazss?a=view

Thanks,

Cindy

On 10/27/09 09:07, F. Wessels wrote:
> Hi,
> 
> how can I find out what the actual value when the default applies to a zfs
property?
> # zfs get checksum mpool
> NAME PROPERTY VALUE SOURCE
> mpool checksum on default
> 
> (In this particular case I know what the value is, either fletcher2 or
fletcher4 depending on the build)
> But how can one find out in general what the actual value is? For any
property.
> 
> thank you,
> 
> Frederik

Thank you for the reply.

I must admit that upon closer inspection alot of properties indeed do present
the actual value.
For the checksum property I used zdb -dddd | grep fletcher to determine wether
it was fletcher2 or fletcher4 was used for checksumming the filesystem. Using
the OS build number to determine whether this was a fletcher2 filesystem
isn''t reliable.

Perhaps this is a candidate for a RFE:
change the value reported by zfs get checksum dataset from "on" to the
actual used algorithm like fletcher2, fletcher4 or sha256

And what about compression? Off is off. But what about "on"? Is that
gzip or lzjb? Same problem.

Thanks,

Frederik
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This message posted from opensolaris.org