On Tue, 2007-07-03 at 21:33 -0400, Nilesh Bansal wrote: > Thanks Saqib for your reply. > > > > Are there any > > > locking issues (files being modified simultaneously) than SAN can not > > > handle. > > yup. You need something like NFS, AFS, GFS, Lustre, or DFS to allow > > multiple machines to access the same storage. > > What happens if only one host mounts the storage for writing and all > other hosts are read-only. > > In our application, the data is stored on one machine and is updated > often. This data is exported to other machines using NFS in a > read-only mode. The problem with NFS is that (I think) it is slow. I > would like to know if read performance from NFS on a gigabit lan is > equivalent to that from a locally attached disk. Our application, > basically a search engine, requires fast reads (iostat shows around > 300 tps and 3000 block reads per second). >From my understanding, the problem is write-caching and sequence of operations on the host that has the write access. Things could be significantly altered by the write-access host in ways that the read- only hosts could not predict. Your read-only host will then read corrupted data, and depending on what it's reading it could really screw things up. I think the only solution is to use a filesystem that is designed for multi-host concurrent access. -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
