[MPICH] Setting the stripe size for a file using mpich2

[Weikuan Yu]

Rob,

I checked that with IOR, the striping hints did not work. But the same works 
for lustre. So I assume the way I give the following hints is right. This is 
just a quick check. However, I did not make a program of my own  for 
in-depth debugging on where the problem might be. FYI, at the end there is 
also some sample output to show this. (I removed an existing file first).

Both the following two sets do not work  for IOR over PVFS2.

#three
IOR_HINT__MPI__striping_unit=262144
IOR_HINT__MPI__striping_factor=2
IOR_HINT__MPI__start_iodevice=3

#or just two of them.
IOR_HINT__MPI__striping_unit=262144
IOR_HINT__MPI__striping_factor=2

Could you let me know how you people verify such hints work for pvfs2, with 
any program? Any time though, I just caught on this thread by curiosity.

--Weikuan

-bash-3.00# /home/wyu/installs/pvfs-2.6.1-tcpmm/bin/pvfs2-rm 
/tmp/pvfs2/iortest ;
-bash-3.00#  /home/wyu/MPICH/mpich2-1.0.3-tcpibvm/bin/mpirun -np 16 
/home/wyu/pario/IOR-tcp -f /home/wyu/fs/pvfs-2.6.1/iorscript.pvfs.16m
IOR-2.9.1: MPI Coordinated Test of Parallel I/O

Run began: Wed Aug 15 09:01:47 2007
Command line used: /home/wyu/pario/IOR-tcp -f 
/home/wyu/fs/pvfs-2.6.1/iorscript.pvfs.16m
Machine: Linux node23

Summary:
         api                = MPIIO (version=2, subversion=0)
         test filename      = pvfs2:/tmp/pvfs2/iortest
         access             = single-shared-file
         clients            = 16 (1 per node)
         repetitions        = 3
         xfersize           = 16 MiB
         blocksize          = 64 MiB
         aggregate filesize = 1 GiB

access    bw(MiB/s)  block(KiB) xfer(KiB)  open(s)    wr/rd(s)   close(s) 
iter------    ---------  ---------- ---------  --------   -------- 
--------   ----write     302.84     65536      16384      0.074419   3.31 
     1.78       0
write     202.10     65536      16384      0.044526   5.03       3.53       1
write     202.24     65536      16384      0.044980   5.02       2.02       2

Max Write: 302.84 MiB/sec (317.55 MB/sec)

Run finished: Wed Aug 15 09:02:01 2007
-bash-3.00# /home/wyu/installs/pvfs-2.6.1-tcpmm/bin/pvfs2-viewdist  -f 
/tmp/pvfs2/iortest
dist_name = simple_stripe
strip_size = 65536
Number of datafiles/servers = 6
Server 0 - tcp://node17:3334, handle: 2454266985 (92492469.bstream)
Server 1 - tcp://node18:3334, handle: 3067833741 (b6db6d8d.bstream)
Server 2 - tcp://node19:3334, handle: 3681400497 (db6db6b1.bstream)
Server 3 - tcp://node20:3334, handle: 4294967253 (ffffffd5.bstream)
Server 4 - tcp://node15:3334, handle: 1227133473 (49249221.bstream)
Server 5 - tcp://node16:3334, handle: 1840700229 (6db6db45.bstream)


Robert Latham wrote:
> On Tue, Aug 14, 2007 at 01:20:51PM -0400, Yu, Weikuan wrote:
>> But stripe size is a static number (64K) in PVFS2. It did not appear
>> customizable by clients to me. or I am not up-to-date on this matter?
> 
> It should take effect for newly created files, or else that's a bug.
> 
> Maybe it's not be available or effective in the mpich2-1.0.2 based MPI
> you're using?
> 
> ==rob
>