> We are seriously considering removing the > layoutcommit call from the file layout client. >From the RFC5661: For block/volume-based layouts, LAYOUTCOMMIT may require updating the block list that comprises the file and committing this layout to stable storage. For file-based layouts, synchronization of attributes between the metadata and storage devices, primarily the size attribute, is required. The control protocol is free to synchronize the attributes before it receives a LAYOUTCOMMIT; however, upon successful completion of a LAYOUTCOMMIT, state that exists on the metadata server that describes the file MUST be synchronized with the state that exists on the storage devices that comprise that file as of the client's last sent operation. Thus, a client that queries the size of a file between a WRITE to a storage device and the LAYOUTCOMMIT might observe a size that does not reflect the actual data written. I understand and agree with the option that control protocol will update the information on the MDFS for file layout type but does the text above not mark layout commit as a consistency boundary even with servers supporting filelayouts? or are we saying that every write or DFS must be synchronized with MDFS thru control protocol for file layout servers? Regards, Suchit Andy Adamson <andros@...> writes: > > > On Jul 1, 2010, at 8:07 PM, Sandeep Joshi wrote: > > Hi Sandeep > > > > > In certain cases, I don't see layoutcommit on a file at all even > > after doing many writes. > > FYI: > > You should not be paying attention to layoutcommits - they have no > value for the file layout type. > > From RFC 5661: > > "The LAYOUTCOMMIT operation commits chages in the layout represented > by the current filehandle, client ID (derived from the session ID in > the preceding SEQUENCE operation), byte-range, and stateid." > > For the block layout type, this sentence has meaning in that there is > a layoutupdate4 payload that enumerates the blocks that have changed > state from being 'handed out' to being 'written'. > > The file layout type has no layoutupdate4 payload, and the layout does > not change due to writes, and thus the LAYOUTCOMMIT call is useless. > > The only field in the LAYOUTCOMMIT4args that might possibly be useful > is the loca_last_write_offset which tells the server what the client > thinks is the EOF of the file after WRITE. It is an extremely lame > server (file layout type server) that depends upon clients for this > info. > > > > > > > > > Client side operations: > > > > open > > write(s) > > close > > > > > > On server side (observed operations): > > > > open > > layoutget's > > close > > > > > > But, I do not see laycommit at all. In terms data written by client > > it is about 4-5MB. > > > > When does client issue laycommit? > > The latest linux client sends a layout commit when the VFS does a > super_operations.write_inode call which happens when the metadata of > an inode needs updating. We are seriously considering removing the > layoutcommit call from the file layout client. > > -->Andy > > > > > > > regards, > > > > Sandeep > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" > > in > > the body of a message to majordomo@... > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@... > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
