Hi Guys, The striping seems to be slightly better than non-striping write, given that my storage is configured with 4OSS, and 48OSD. each OSD is 8+2 Raid 6 of 24TB capacity. But still the performance is around 100MB/sec. On a single haswell core, I'm able to get 1GB/sec with dd buffered IO.
My questions are: 1. Does librados use direct IO? 2. Is there option to leverage page cache? 3. What is the strategy to get the peak bandwidth on a rados object store? 4. Can I use MPI for parallel IO? Best, Jialin NERSC On Wed, May 30, 2018 at 11:08 AM, Jialin Liu <jaln...@lbl.gov> wrote: > Thanks Kefu. > > Best, > Jialin > NERSC > > On Tue, May 29, 2018 at 11:52 PM, kefu chai <tchai...@gmail.com> wrote: > >> On Wed, May 30, 2018 at 11:53 AM, Jialin Liu <jaln...@lbl.gov> wrote: >> > Hi Brad, >> > >> > You are correct. the librados.so has the symbol but what I copied is a >> wrong >> > file. >> > Now I can test the striper api with the previous C example and this cpp >> > example: >> > http://mrbojangles3.github.io/ceph/systems/striping/alignmen >> t/2017/05/28/Ceph-Stripe/ >> > Both are working, but I haven't got any performance number yet. >> > ps. I also found that the stripe unit must be set before object_size >> > properly. >> > >> > Thanks much. >> > >> > Best, >> > Jialin >> > NERSC >> > >> > >> > On Tue, May 29, 2018 at 7:11 PM, Brad Hubbard <bhubb...@redhat.com> >> wrote: >> >> >> >> On Wed, May 30, 2018 at 11:52 AM, Jialin Liu <jaln...@lbl.gov> wrote: >> >> > Thanks Brad, >> >> > I run nm on those .so file, it prints 'no symbol' >> >> >> >> OK, well you need to link to a library that exports that symbol (has >> >> it defined in its Text section). I suspect you'll find it is defined >> >> in libceph-common.so so try linking to that explicitly. >> >> please note, libceph-common does not exist in jewel (i.e. v10.2.10) >> yet. it was introduce in luminous. and libceph-common is not supposed >> to be linked against by rados application directly. it is an internal >> library and is linked by librados, libradosstriper and other rados >> tools/daemons. >> >> >> >> >> > >> >> > Then with ldd librados.so, I don't see the libceph-common.so, >> instead: >> >> >> >> >> >> jialin@cori12: ldd librados.so >> >> >> linux-vdso.so.1 (0x00002aaaaaacf000) >> >> >> libboost_thread-mt.so.1.53.0 >> >> >> =>/rados_install/lib/libboost_thread-mt.so.1.53.0 >> (0x00002aaaad24d000) >> >> >> libboost_system-mt.so.1.53.0 => >> >> >> /rados_install/lib/libboost_system-mt.so.1.53.0 >> (0x00002aaaad464000) >> >> >> libssl3.so => /usr/lib64/libssl3.so (0x00002aaaad668000) >> >> >> libsmime3.so => /usr/lib64/libsmime3.so (0x00002aaaad8b4000) >> >> >> libnss3.so => /usr/lib64/libnss3.so (0x00002aaaadadb000) >> >> >> libnssutil3.so => /usr/lib64/libnssutil3.so (0x00002aaaaddfe000) >> >> >> libplds4.so => /usr/lib64/libplds4.so (0x00002aaaae02c000) >> >> >> libplc4.so => /usr/lib64/libplc4.so (0x00002aaaae230000) >> >> >> libnspr4.so => /usr/lib64/libnspr4.so (0x00002aaaae435000) >> >> >> libpthread.so.0 => /lib64/libpthread.so.0 (0x00002aaaae673000) >> >> >> libdl.so.2 => /lib64/libdl.so.2 (0x00002aaaae890000) >> >> >> libuuid.so.1 => /usr/lib64/libuuid.so.1 (0x00002aaaaea94000) >> >> >> librt.so.1 => /lib64/librt.so.1 (0x00002aaaaec99000) >> >> >> libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00002aaaaeea1000) >> >> >> libm.so.6 => /lib64/libm.so.6 (0x00002aaaaf22a000) >> >> >> libc.so.6 => /lib64/libc.so.6 (0x00002aaaaf527000) >> >> >> libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00002aaaaf8c8000) >> >> >> libz.so.1 => /lib64/libz.so.1 (0x00002aaaafadf000) >> >> >> /lib64/ld-linux-x86-64.so.2 (0x00002aaaaaaab000) >> >> >> >> Things were obviously different in jewel but the concept remains the >> >> same. For each external symbol your binary requires you need to link >> >> to a library that exports that symbol so finding the library that >> >> exports the symbols in the error message should resolve the error. >> >> >> >> > >> >> > >> >> > I also found this thread: http://tracker.ceph.com/issues/14788 >> >> > which looks similar to the error I run into, and that thread >> mentioned >> >> > the >> >> > version between the headers file and the .so file, I think in my case >> >> > both >> >> > of them are v10.2.10, which should ok. >> >> > >> >> > Best, >> >> > Jialin, >> >> > >> >> > On Tue, May 29, 2018 at 6:17 PM, Brad Hubbard <bhubb...@redhat.com> >> >> > wrote: >> >> >> >> >> >> On Wed, May 30, 2018 at 10:42 AM, Jialin Liu <jaln...@lbl.gov> >> wrote: >> >> >> > Hi, >> >> >> > I'm trying to use the libradosstriper api, but having some >> trouble in >> >> >> > linking to lradosstriper. I copied only the `required' libraries >> from >> >> >> > an >> >> >> > pre-installed ceph (10.2.10), and put them under my local >> directory >> >> >> > /rados_install/lib and rados_install/include, on a linux machine. >> >> >> > >> >> >> > /rados_install/lib: >> >> >> >> >> >> >> >> libboost_date_time.so.1.53.0 libboost_system.so.1.53.0 >> >> >> >> libboost_filesystem-mt.so.1.53.0 libboost_thread-mt.so.1.53.0 >> >> >> >> libboost_filesystem.so.1.53.0 libcephfs.so.1.0.0 >> >> >> >> libboost_iostreams-mt.so.1.53.0 >> >> >> >> libboost_iostreams.so.1.53.0 >> >> >> >> libboost_random-mt.so.1.53.0 librados.so.2.0.0 >> >> >> >> libboost_regex.so.1.53.0 librados_tp.so.2.0.0 >> >> >> >> libboost_system-mt.so.1.53.0 libradosstriper.so.1.0.0 >> >> >> >> libcephfs.so librados.so libradosstriper.so >> >> >> > >> >> >> > >> >> >> > /rados_install/include: >> >> >> >> >> >> >> >> |-- rados >> >> >> >> | |-- buffer.h -> ../buffer.h >> >> >> >> | |-- buffer_fwd.h -> ../buffer_fwd.h >> >> >> >> | |-- crc32c.h -> ../crc32c.h >> >> >> >> | |-- inline_memory.h -> ../inline_memory.h >> >> >> >> | |-- librados.h >> >> >> >> | |-- librados.hpp >> >> >> >> | |-- librgw.h >> >> >> >> | |-- memory.h -> ../memory.h >> >> >> >> | |-- objclass.h >> >> >> >> | |-- page.h -> ../page.h >> >> >> >> | |-- rados_types.h >> >> >> >> | |-- rados_types.hpp >> >> >> >> | `-- rgw_file.h >> >> >> >> `-- radosstriper >> >> >> >> |-- libradosstriper.h >> >> >> >> `-- libradosstriper.hpp >> >> >> > >> >> >> > >> >> >> > The test code is simple, as attached, and I compiled it with >> dynamic >> >> >> > linking: >> >> >> >> >> >> >> >> cc -L/rados_install/lib -I/rados_install/include -o librados_test >> >> >> >> librados_test.c -lrados -lradosstriper >> >> >> > >> >> >> > >> >> >> > But got the following message, can anyone plz advise? >> >> >> > >> >> >> >> >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::ptr::ptr(ceph::buffer::ptr&&)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::ptr::operator=(ceph::buffer::ptr&&)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `librados::IoCtx::remove(std::string const&, int)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::list::iterator::iterator(ceph::buffer::list*, >> >> >> >> unsigned >> >> >> >> int)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::list::is_provided_buffer(char const*) const' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::list::append(ceph::buffer::ptr&&)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::list::iterator::iterator(ceph::buffer::list*, >> >> >> >> unsigned >> >> >> >> int, >> >> >> >> std::_List_iterator<ceph::buffer::ptr>, unsigned int)' >> >> >> >> /rados_install/lib/libradosstriper.so: undefined reference to >> >> >> >> `ceph::buffer::list::list(ceph::buffer::list&&)' >> >> >> >> >> >> Try doing the following in your lib directory. >> >> >> >> >> >> $ nm -A -C *.so|grep is_provided_buffer >> >> >> libceph-common.so:0000000000223df0 T >> >> >> ceph::buffer::list::is_provided_buffer(char const*) const >> >> >> librados.so:00000000000bfef0 T >> >> >> ceph::buffer::list::is_provided_buffer(char const*) const >> >> >> libradosstriper.so: U >> >> >> ceph::buffer::list::is_provided_buffer(char const*) const >> >> >> >> >> >> 'ldd librados.so' shows it links to libceph-common.so so I suspect >> you >> >> >> may need that library. >> >> >> >> >> >> Don't forget that you need to tell the linker where to find these >> >> >> libraries at runtime so you will need to pass something like >> >> >> '-Wl,-rpath=/rados_install/lib' to the compiler so it finds the >> >> >> correct versions of the libraries (you can check which ones it will >> >> >> find with 'ldd librados_test'. >> >> >> >> >> >> HTH >> >> >> >> >> >> > >> >> >> > >> >> >> > Best, >> >> >> > Jialin >> >> >> > NERSC >> >> >> > >> >> >> > _______________________________________________ >> >> >> > ceph-users mailing list >> >> >> > ceph-users@lists.ceph.com >> >> >> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> > >> >> >> >> >> >> >> >> >> >> >> >> -- >> >> >> Cheers, >> >> >> Brad >> >> > >> >> > >> >> >> >> >> >> >> >> -- >> >> Cheers, >> >> Brad >> > >> > >> > >> > _______________________________________________ >> > ceph-users mailing list >> > ceph-users@lists.ceph.com >> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > >> >> >> >> -- >> Regards >> Kefu Chai >> > >
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