-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 RBD can be safely mounted on multiple machines at once, but the file system has to be designed for such scenarios. File systems like ext, xfs, btrfs, etc are only designed to be accessed by a single system. Clustered file systems like OCFS, GFS, etc are designed to have multiple discrete machines access the file system at the same time. As long as you use a clustered file system on RBD, you will be OK. Now, if that performs better than CephFS, is a question you will have to answer through testing. - ---------------- Robert LeBlanc PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 On Wed, Jul 22, 2015 at 1:17 PM, Lincoln Bryant wrote: > Hi Hadi, > > AFAIK, you can’t safely mount RBD as R/W on multiple machines. You could > re-export the RBD as NFS, but that’ll introduce a bottleneck and probably > tank your performance gains over CephFS. > > For what it’s worth, some of our RBDs are mapped to multiple machines, > mounted read-write on one and read-only on the others. We haven’t seen any > strange effects from that, but I seem to recall it being ill advised. > > —Lincoln > > On Jul 22, 2015, at 2:05 PM, Hadi Montakhabi wrote: > > Hello Cephers, > > I've been experimenting with CephFS and RBD for some time now. > From what I have seen so far, RBD outperforms CephFS by far. However, there > is a catch! > RBD could be mounted on one client at a time! > Now, assuming that we have multiple clients running some MPI code (and doing > some distributed I/O), all these clients need to read/write from the same > location and sometimes even the same file. > Is this at all possible by using RBD, and not CephFS? > > Thanks, > Hadi > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > _______________________________________________ > ceph-users mailing list > ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -----BEGIN PGP SIGNATURE----- Version: Mailvelope v0.13.1 Comment: https://www.mailvelope.com wsFcBAEBCAAQBQJVr+6rCRDmVDuy+mK58QAAbaIP/RhTTsYhx1boWdec8PIb RBYP7rV1Pg2X/QESNWFZA7waqyymfSJgbLZ+TAuHCfUdLCWAE9lerNAs5Cdn ZvLx1Z56s9DsYjh/AFawKAq2tIBUzHOsPZORrUI1HkU2Y3vf9IzYOpUNcxUF 2sY5pGOM0NQDdojsuxskqHP47RckdUdiMAb7UWK7LYHCJJKlzvfFBfp7XT9+ sD4Uy/3Wos0KBH60Oxt8ueGyDCd3EYa1fV8+2k/uJ447XRujv9RC3fXth+oE QYKhNNxi5la0awChs00hfDx7SGlOoq5dy7POAmImo9Y/eoZNuiBSpiUtXAT/ kWvshIUKOUq6A06boEGNDDyGVjaOHUBEZtA1Vpmkj53oY4eDugNKUxMCnFEo /TVgMgjzMM90+u9E7l/Bx7H497HoIAJkhN/9kFK+t9CWySX8I/A1fZ9XI/hs hsVHPvhJrQW/8eHRERJbVEItJZP5EI1wkzpZanpsmimeRghqy2S87TYg6Ged 7Eyt7kpBqUXn+i3VJ0LBvlXC81O0SEA32PEN8Zbv/jFdyHJ4nmXz/WWs/M4p ZseYV/5AHtov+Kbbm8C3CyOO3M8zx5fGPHGNwr+PCYJiQxNCaZPYJ3fB98hn IQhD2f0KYc6cDY19ZtreXNE6ITuZ78n8LulOSlU1VSTPdv/pWBmkCFEV4f3f k6BV =Zvwe -----END PGP SIGNATURE----- _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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