Hi David, We talked a bit about a similar topic on DataNode sockets a while back. Any feedback on the DataNode disk access?
On Thu, Mar 5, 2020 at 4:16 PM Mania Abdi <abdi...@husky.neu.edu> wrote: > Hello everyone > > I have a question regarding HDFS, data node code version 2.7.2. I have > posted my question as Jira issue > <https://issues.apache.org/jira/projects/HDFS/issues/HDFS-15206>. > > I have observed that datanode issues sequential synchronous 64KB reads to > local disk and add then send it to user and wait for the acknowledgement > from the user. I was wondering why HDFS community did not use file mapping > or asynchronous read from disk? This could allow disk scheduler to perform > sequential reads from disk or perform read-ahead and prefetching. Is it > something that could lead to performance improvement or not. > > I would appreciate if you could help me to find the answer to this issue > from Hadoop community > perspective. > > I asked from apache members and they told me that the version I am pointing > to is old and this part of code written from scratch for modern SSDs. Could > you please help me to find at which version this modification happened? and > Where I can find it. > > Many thanks > Mania >
