On Tue, 12 Apr 2011, Sylar Shen wrote: > Hi developers, > I know that the following question may not be relative to Ceph but > this confuses me a lot. > I am testing the function of re-exporting nfs by command "dd" without > using buffer. > That means I would like my data to be written to Ceph DFS directly > without passing by the buffer of client or nfs-client. > Here is my test architecture. Hope you could understand what I am > trying to express.....:p > ------------------------------------------------------------------------------ > nfs ceph protocol > Client <------------>Ceph-Client <-------------------> Ceph DFS > ------------------------------------------------------------------------------ > I used the command "dd if=/dev/zero of=/mnt/ceph/test bs=64k > count=10000 oflag=dsync" > My purpose was to write the data from the client to Ceph DFS through > Ceph-client. > Ceph DFS was mounted by Ceph-client using Ceph protocol and > Ceph-client was mounted by client using nfs protocol. > I know that my dd command with argument oflag=dsync would write the > data to Ceph-client without using buffer on the client. > But I want my Ceph-client could also just pass the data to Ceph DFS > without using its buffer. > So.....is there any way I can run my scenario? > Or in other words, is there any method I can assure that Ceph-client > won't do the buffer task itself? I think what you're looking for is the 'sync' option in /etc/exports on the ceph-client machine. See 'man 5 exports'. That will slow things down considerably but will give you the consistency and safety you're looking for. sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
