Hello Anna,
I believe your snapshot is indeed zero (0) at first.  Then as the data changes, your snapshot is holding on to it's read-only blocks.  So it makes sense that the snapshot is growing.  The more data you turn over, the bigger thw snapshot will be.

A good test:
Create a small volume, dump some data into it and then take a snapshot.  Examine the snapshot carefully.

Now completely overwrite (delete and then re-write) the data and then look at the same snapshot again.

Theory: your snapshot keeps changing because your 'active filesystem' is changing.

Cheers ......


Sent from my network synchronized laptop running Microsoft Outlook 2003 (www.microsoft.com)

 -----Original Message-----
From:   Anna M [mailto:annpurna@gmail.com]
Sent:   Monday, April 07, 2008 10:18 AM Pacific Standard Time
To:     toasters@mathworks.com
Subject:        Re: impact of setting snap reserve to 0


Since I am totally new to the world of filers, I would really appreciate if
you can just explain me as to why the snapshot size for a newly created
flexclone volume is not zero? After all the source for it also was a
snapshot.

The issues in space calculation for a newly clones volume is actually
because of the changes in the snapshot size for this vol.
For one of my newly cloned flexclone volume I am seeing that with in 3
minutes, the snapshot size reported is altered from
/vol/prod_v/        475777656KB 400203924KB 75573732KB      84%
/vol/prod_v/
/vol/prod_v/.snapshot        0KB 74248140KB        0KB     ---%
/vol/prod_v/.sn

to
/vol/prod_v/        475777656KB 325971708KB 149805948KB      69%
/vol/prod_v/
/vol/prod_v/.snapshot        0KB    16112KB        0KB     ---%
/vol/prod_v/.snapshot


Similarly the agg show_space output that I took at the same time as I took
above df command output shows change in allocated and Used space values for
this volume as:
prod_v                         75574680KB            32KB          volume
.
...
prod_v                        149823776KB         17816KB          volume

O/p for both these commands are still changing... We have found that values
take approx 19 minutes to settle down...19 minutes seems to be a BIG
duration :-(

Any help in this regard will really be appreciated.

-Anna


bluezman wrote:
>
> Anna M wrote:
>> snip
>>  
>
>> Any clue as to why would this be heppening? Can it be because snap
>> reserve
>> is not set properly(we have set it to zero)?
>>  
>
> i believe that when you take a clone, it takes a snapshot of the src,
> since your snapshot space comes out of the actual volume, you will see
> the size change
>
> correct me if i am wrong.
>
>

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