Monitoring ZFS IO

[Bob Friesenhahn]

On Fri, 2 Dec 2011, Jason Hellenthal wrote:
>>>
>>> I want to see how many bytes or KB have been read and written to a given
>>> zpool since creation (as in the newer of uptime or zpool creation) on the
>>> system.
>>
>> This implies that these statistics would need to be stored in the pool
>> itself, which implies that the statistics need to be periodically
>> written (e.g. in each transaction group) as a form of metadata.
>>
>
> I thought this was ( df -[h,b,m,g]) output... ;)

Apparently the term "creation" was meant to mean "since boot" rather 
than since filesystem creation.  Regardless, it is possible to write 
thousands of times more data to a filesystem than it contains.  This 
means that 'df' won't do the job.

It would be nice if the zfs pool could store its own performance data 
since the dawn of time.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/