[Pvfs2-developers] Changing the number of I/O servers

[Christina Patrick]

Hi Kevin,

Yes, I am using mpich2-1.0.8 and pvfs2.8.0.

Regards,
Christina.

On Tue, Jul 14, 2009 at 12:40 PM, Kevin Harms<harms at alcf.anl.gov> wrote:
> Christina,
>
>  you are using MPICH2 and the ad_pvfs2 romio module?
>
> kevin
>
> On Jul 14, 2009, at 9:12 AM, Christina Patrick wrote:
>
>> Hi Everybody,
>>
>> I want to use MPI hints to create a striped file across a subset of
>> the pvfs2 servers. For that I use, the hints "striping_unit" and
>> "striping_factor". I have a set of three I/O servers. However, I want
>> to create the file only on one I/O server. I specified "striping_unit"
>> = 65536 and "striping_factor" = 1. However, after the file is created,
>> I get the following results:
>>
>> pvfs2-viewdist -f /home/mdl/patrick/pvfs2/oneserver
>> dist_name = simple_stripe
>> dist_params:
>> strip_size:65536
>>
>> Metadataserver: tcp://aum14:7000
>> Number of datafiles/servers = 3
>> Datafile 0 - tcp://aum15:7000, handle: 9223372036854775298
>> (7ffffffffffffe02.bstream)
>> Datafile 1 - tcp://aum13:7000, handle: 4611686018427387650
>> (3fffffffffffff02.bstream)
>> Datafile 2 - tcp://aum14:7000, handle: 4611686018427387905
>> (4000000000000001.bstream)
>>
>> Am I missing something? I wanted to use this hint, so that I don't
>> have to reconfigure the servers everytime, I want to change the number
>> of I/O servers.
>> Could somebody please help me?
>>
>> Thanks and Regards,
>> Christina.
>>
>> PS: The extract from my program which does this:
>>    79   MPI_Info_create(&file_info);
>>    80
>>    81   if(argc > 1) {
>>    82     stripe_unit = atoi(argv[1]);
>>    83     sprintf(stripe_unit_str, "%d", stripe_unit);
>>    84     MPI_Info_set(file_info, "striping_unit", stripe_unit_str);
>>    85   }
>>    86
>>    87   if(argc > 2) {
>>    88     stripe_factor = atoi(argv[2]);
>>    89     sprintf(stripe_factor_str, "%d", stripe_factor);
>>    90     MPI_Info_set(file_info, "striping_factor", stripe_factor_str);
>>    91   }
>>    92
>>    93   MPI_File_open(MPI_COMM_WORLD, fname, MPI_MODE_CREATE |
>> MPI_MODE_WRONLY, file_info, &fhandle);
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>
>