example timings

[Wei-keng Liao]

Can you run the following command on the directory where your 
output files will be stored?

   lfs getstripe <dir path> |grep stripe

This will show the stripe info of a Lustre directory.

Wei-keng


On Wed, 18 Jul 2007, michael bane wrote:

> On Wed, 2007-07-18 at 12:04 -0500, Wei-keng Liao wrote:
>> Michael,
>>
>> I noticed that your codes write the output files to your home directory
>> which is NFS mounted. Usually, NFS performance for parallel I/O is very
>> slow.
>
>
> Wei-keng, I'm confused as to your assertion that my home filestore is
> NFS mounted. I can't see how one can tell from the code or graph! I'll
> check with the sysAdmin tomorrow but it seems to me that both
> directories (for executable and output files) are Lustre:
>
> ~$ df -h ~/Fortran/MPI/parallel_netCDF/ ~/tmp/test_par_netcdf/
> Filesystem            Size  Used Avail Use% Mounted on
> 1 at elan0:/mdt_horace1.nec.1/clientelan
>                      1.5T  283G  1.2T  20% /home/horace
> 1 at elan0:/mdt_horace1.nec.1/clientelan
>                      1.5T  283G  1.2T  20% /home/horace
>
> ~$ mount | grep -e 1 at elan0:/mdt_horace1.nec.1/clientelan
> 1 at elan0:/mdt_horace1.nec.1/clientelan on /home/horace type lustre
> (rw,user_xattr,acl)
>
> ~$
>
>> Can you try write to the Lustre file system? I can see Lustre is available
>> on your machine. You may also want to configure a Lustre directory with
>> multiple stripe counts to increase the I/O performance.
>
> I've no idea how Lustre has been set up and have forwarded your comments
> to our sysAdmin for comment.
>
> Thanks, Michael
>