[Pvfs2-users] An I/O test

[hawaii]

Another test to copy the 2GB single file confirms that pvfs2 works better
with big files. A few snapshots are:

(1) From local to pvfs2 using
cp: 4m57s
pvfs2-cp: Wrote 2057207616 bytes in 21.67 sceonds. 90.5 MB/seconds

(2) From pvfs2 to pvfs2 using
pvfs2-cp: Wrote ... in 42.82 seconds. 45.81 MB/seconds
cp: 13m4s




On Thu, Sep 4, 2008 at 11:37 AM, Kyle Schochenmaier <kschoche at gmail.com>wrote:

> It would be interesting to know what the numbers are for copying
> pvfs2->local_memory  and then back, local_memory->pvfs2 and compare
> that to doing pvfs2->pvfs2.
> If I were wanting to further look at these results and try to discern
> what the slow parts are, some important things to note are cpu
> utilization on the servers and clients.
>
> You should also ideally have a difference in cpu utilization when you
> do 'cp -r'  vs. the pvfs2-cp  which doesnt go through the kernel
> module.
>
> What is the cpu load on the client, I/O, MD servers?
> If you find that the MD server is getting hit heavily, you might be
> able to startup a second MD server, maybe even on the same box with
> multiple-cores.
>
> I'm also assuming you are using very small files.  PVFS2 does not
> particularly shine with large numbers of small files in general,
> especially when compared to systems that do caching (nfs).
> From what I understand about whats going on in the servers during
> these operations, these numbers kind of fall in line with what I would
> have expected.
>
> Just some random thoughts, good luck!
>
> Kyle
>
> On Thu, Sep 4, 2008 at 4:13 PM, hawaii <forapart at gmail.com> wrote:
> > A pvfs2 I/O test
> > (for comments)
> > ===================
> >
> > pvfs version: 2.7.1
> > configuration: 1 meta server + 3 data servre. Each server has 2 cpus
> > reserved
> >
> > Tests: within pvfs2; from pvfs2 to local; nfs
> > Use pvfs2-cp-r, pvfs2-cp-r.pl, and cp
> > (thanks Mark Bartelt for providing pvfs2-cp-r and pvfs2-cp-r.pl)
> >
> > Source direcotry: WRF
> > df -k WRF
> >   lots of subdirctories
> > 511868  WRF
> >
> > (1) pvfs2 -> pvfs2
> >
> > time pvfs2-cp-r WRF tmp
> > real    4m16.414s
> > user    0m38.385s
> > sys     0m31.874s
> > I/O 2 MB/s
> >
> > time pvfs2-cp-r.pl WRF tmp
> > Copying files from "WRF" to "tmp/WRF" using pvfs2-cp
> > real    4m21.573s
> > user    0m38.741s
> > sys     0m32.293s
> > I/O 1.96 MB/s
> >
> > time cp -rp WRF tmp
> > Lots of 0 files (unreliable)
> > real    7m21.473s
> > user    0m0.100s
> > sys     0m5.792s
> > I/O 1.16 MB/s
> >
> > (2) pvfs2 -> local hard drive
> >
> > time pvfs2-cp-r.pl /pvfs2-dir/WRF /home/user
> > Copying files from "/pvfs2-dir/WRF" to "/home/user/WRF" using pvfs2-cp
> > real    1m19.311s
> > user    0m19.008s
> > sys     0m29.327s
> > I/O     6.4 MB/s
> >
> > time pvfs2-cp-r /pvfs2-dir/WRF /home/user
> > real    1m10.739s
> > user    0m20.609s
> > sys     0m30.021s
> > I/O     7.25 MB/s
> >
> > time cp -rp /pvfs2-dir/WRF /home/user
> > Lots of 0 files (unreliable)
> > real    1m34.071s
> > user    0m0.113s
> > sys     0m3.906s
> > I/O     5.45 MB/s
> >
> > (3) cp an nfs file to local disk
> > 2057207616 t.dat
> > time cp -p /nfs-dir/t.dat /home/usr/.
> > real    2m55.894s
> > user    0m0.257s
> > sys     0m6.946s
> > Read 11.7 MB/s
> >
> > Conclusion from this test:
> > (1) pvfs2-cp-r is the fastest and cp -r is the slowest
> > (2) it is slower to copy directory inside pvfs2 than to local disk
> > (3) I/O pvfs2 is much slower than nfs !!!
> > Any comments on the results?
> > _______________________________________________
> > Pvfs2-users mailing list
> > Pvfs2-users at beowulf-underground.org
> > http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
> >
> >
>
>
>
> --
> Kyle Schochenmaier
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.beowulf-underground.org/pipermail/pvfs2-users/attachments/20080904/68cf6505/attachment.htm