+1 for approach A. On Thu, 11 Apr 2019, 12:23 pm Akira Ajisaka, <aajis...@apache.org> wrote:
> The Approach A looks good to me. > > Thanks, > Akira > > On Thu, Apr 11, 2019 at 2:30 PM Xiaoqiao He <xq.he2...@gmail.com> wrote: > > > > Hi forks, > > > > The current implementation of RBF is not sensitive about data locality, > > since NameNode could not get real client hostname by invoke > > Server#getRemoteAddress when RPC request forward by Router to NameNode. > > Therefore, it will lead to several challenges, for instance, > > > > - a. Client could have to go for remote read instead of local read, > > Short-Circuit could not be used in most cases. > > - b. Block placement policy could not run as except based on defined > > rack aware. Thus it will loss local node write. > > > > There are some different solutions to solve data locality issue after > > discussion, some of them will change RPC protocol, so we look forward to > > furthermore suggestions and votes. HDFS-13248 is tracking the issue. > > > > - Approach A: Changing IPC/RPC layer protocol > (IpcConnectionContextProto > > or RpcHeader#RpcRequestHeaderProto) and add extra field about client > > hostname. Of course the new field is optional, only input by Router > and > > parse by Namenode in generally. This approach is compatibility and > Client > > should do nothing after changing. > > - Approach B: Changing ClientProtocol and add extra interface > > create/append/getBlockLocations with additional parameter about client > > hostname. As approach A, it is input by Router and parse by Namenode, > and > > also is compatibility. > > - Approach C: Solve write and read locality separately based on > current > > interface and no changes, for write, hack client hostname as one of > favor > > nodes for addBlocks, for read, reorder targets at Router after > Namenode > > returns result to Router. > > > > As discussion and evaluation in HDFS-13248, we prefer to change IPC/RPC > > layer protocol to support RPC data locality. We welcome more suggestions, > > votes or just give us feedback to push forward this feature. Thanks. > > > > Best Regards, > > Hexiaoqiao > > > > reference > > [1] https://issues.apache.org/jira/browse/HDFS-13248 > > [2] https://issues.apache.org/jira/browse/HDFS-10467 > > > > [3] https://issues.apache.org/jira/browse/HDFS-12615 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org > For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org > >
