It sounds like you are looking for a shared file system like Sun's QFS? Take a look here http://opensolaris.org/os/project/samqfs/What_are_QFS_and_SAM/
Writes from multiple hosts go through the metadata server, basically, that handles locking and update problems. I believe there are other open source shared file systems around if you are trying to specifically address the sharing problem. David Olsen wrote: >> On 27/08/2007, at 12:36 AM, Rainer J.H. Brandt wrote: >> >>> Sorry, this is a bit off-topic, but anyway: >>> >>> Ronald Kuehn writes: >>> >>>> No. You can neither access ZFS nor UFS in that >>>> >> way. Only one >> >>>> host can mount the file system at the same time >>>> >> (read/write or >> >>>> read-only doesn't matter here). >>>> >>> I can see why you wouldn't recommend trying this >>> >> with UFS >> >>> (only one host knows which data has been committed >>> >> to the disk), >> >>> but is it really impossible? >>> >>> I don't see why multiple UFS mounts wouldn't work, >>> >> if only one >> >>> of them has write access. Can you elaborate? >>> >> Even with a single writer you would need to be >> concerned with read >> cache invalidation on the read-only hosts and >> (probably harder) >> ensuring that read hosts don't rely on half-written >> updates (since >> UFS doesn't do atomic on-disk updates). >> >> Even without explicit caching on the read-only hosts >> there is some >> "implicit caching" when, for example, a read host >> reads a directory >> entry and then uses that information to access a >> file. The file may >> have been unlinked in the meantime. This means that >> you need atomic >> reads, as well as writes. >> >> Boyd >> _______________________________________________ >> zfs-discuss mailing list >> zfs-discuss@opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/zfs-discu >> ss >> > > It's worse than this. Consider the read-only clients. When you access a > filesystem object (file, directory, etc.), UFS will write metadata to update > atime. I believe that there is a noatime option to mount, but I am unsure as > to whether this is sufficient. > > my 2c. > --Dave > > > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
