Re: best practice of using parallel hdf5

Hi Quincey,

Thanks for the information. It's very helpful. I guess I will have to
create a new file for every record instead.

Regards,

Eh


Quincey Koziol wrote:

>
> On Nov 27, 2006, at 8:24 PM, Eh Tan wrote:
>
>>
>> In the event of system crash, how can I prevent the file corruption  and
>> how can I minimize the loss of data?
>> Should I flush the buffer after each output, or close the dataset  after
>> each output, or save each record in a new datagroup, or save each 
>> record
>> in a new file? How much of data loss would I expect in the worst
>> scenario (e.g., the system crashes during disk I/O)?
>
>
>     Generally, it's a good idea to call H5Fflush (or the equivalent 
> netCDF API call) after each major "phase" of writing to the file.  
> This will flush metadata changes out to the disk.  However, it is 
> still possible that incremental changes may be made to the file as 
> metadata is evicted from the HDF5 internal caches that would create a 
> "corrupt" file if the rest of the changes don't make it into the 
> file.  Flushing too often may create additional I/O though, so you'll 
> need to find a balance that's appropriate for your application.
>
>    


-- 
Eh Tan
Staff Scientist
Computational Infrastructure for Geodynamics
2750 E. Washington Blvd. Suite 210
Pasadena, CA 91107
(626) 395-1693
http://www.geodynamics.org

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