we're running a CDP Private Cloud Base Cluster with actually 6 Nodes. All 6 Nodes running fully on SSD storage. I found out that HDFS thinks the SSDs are normal disk, because it is not configured as SSD storage like this --> "[SSD]/grid/n/dn", actually its "/grid/n/dn". Now we're planning to add four other servers from an older cluster with normal disks.
My action plan is as follows:
1. configure existing storage/server to SSD -> "[SSD]/grid/n/dn"
2. add the other four server an configure it -> "[DISK]/grid/n/dn"
3. restart recommended services
I've got the following questions:
- Will HDFS distribute the blocks across all nodes (SSD and disk?) without any storage policy configured? So that we have a homogeneous storage.
- How will services react to this changes in storage, for example HBase?
- If we configure a homogeneous storage, as i described: does reconfiguring the storage paths of the Datanodes to SSDs add any value/benefit at all?
Thanks for your help!