HP Proliant DL 380 G7 Memory Selection

[Mark-C]

HI Everyone,

I am new to HPE Community and hope you could help with a quick advise. My group inherited 3 HP Proliant DL 380 G7 servers. 

1. HP Proliant DL 380 G7 1x146GB SAS, no ram

2. HP Proliant DL 380 G7 2x600Gb SAS +2x146Gb 18x4GB DIMM

3. HP Proliant DL 380 G7 8x600 Gb 8x8GB DIMM

My question is about the recomended memory & HDD configuration if I would like to get most our of this hardware for analytics cluster for R&D projects that include Apache Spark, Hadoop, Mesos, etc plus I would need spare capacity to deploy own services. Lastly but not least I was wondering if I could install NVidia GTX 1080Ti (x16 ePCI)  for Machine Learning.

I plan on using Ubuntu 16.04.2 LTS.

for Spark/Hadoop cluster I planned on dedicating at least one or two servers to host data-nodes and workers therefore highest speed memory with at most capacity would be needed probably maximizing the storage size as well for HDFS. Second should host Mesos, cluster node and resource management applications probably on 2 VMs. any spare capacity may host other services like Kafka, NiFi. Kylin

I also need to squise in Solr/ElasticSearch instance, than KNIME, TIBCO Servers with Simba ODBC driver.

Thanks in advance for your time