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

[Christina Patrick]

Hi,

I tried the pvfs2-cp command and here are the results:
----------------------------------------
$ pvfs2-cp -n 1 /home/mdl/patrick/pvfs2/oneserver /home/mdl/patrick/pvfs2/s1
$ pvfs2-viewdist -f /home/mdl/patrick/pvfs2/s1
dist_name = simple_stripe
dist_params:
strip_size:65536

Metadataserver: tcp://aum14:7000
Number of datafiles/servers = 3
Datafile 0 - tcp://aum14:7000, handle: 6917529027641081849
(5ffffffffffffff9.bstream)
Datafile 1 - tcp://aum15:7000, handle: 9223372036854775300
(7ffffffffffffe04.bstream)
Datafile 2 - tcp://aum13:7000, handle: 4611686018427387652
(3fffffffffffff04.bstream)
----------------------------------------
$ pvfs2-cp -n 2 /home/mdl/patrick/pvfs2/oneserver /home/mdl/patrick/pvfs2/s2
$ pvfs2-viewdist -f /home/mdl/patrick/pvfs2/s2
dist_name = simple_stripe
dist_params:
strip_size:65536

Metadataserver: tcp://aum14:7000
Number of datafiles/servers = 2
Datafile 0 - tcp://aum14:7000, handle: 6917529027641081848
(5ffffffffffffff8.bstream)
Datafile 1 - tcp://aum13:7000, handle: 4611686018427387397
(3ffffffffffffe05.bstream)
----------------------------------------

It seems that the striping does not work only when we specify *one*
server as input (but apparently works if you specify anything other
than one).
Since I have only 3 I/O servers configured currently, this is all I could try.
I also tried my program with 2 I/O servers and it worked as shown above.

Thanks and Regards,
Christina.

On Wed, Jul 15, 2009 at 2:42 PM, Rob Latham<robl at mcs.anl.gov> wrote:
> On Wed, Jul 15, 2009 at 02:26:07PM -0400, Christina Patrick wrote:
>> Hi Rob,
>>
>> I am willing to try it out. However, I don't know how to do so using pvfs2-cp.
>> Sorry to trouble you, but could you please tell me how to do it.
>
> No problem.   Find some large-ish file (about 1MB should do) and copy
> it to your pvfs volume like so:
>
> /usr/local/pvfs2/bin/pvfs2-cp -n 1 <src> /pvfs/mountpoint/dir/<dest>
>
> and try that also with a few different values of -n
>
> ==rob
> --
> Rob Latham
> Mathematics and Computer Science Division
> Argonne National Lab, IL USA
>