Most components have already arrived and this is how my cluster looks like now:
I am still waiting for additional storage to come. So far there is about 4TB of space on HDFS:
$ hadoop fs -df -h Filesystem Size Used Available Use% hdfs://h1.home:8020 3.8 T 39.5 G 3.6 T 1%
Out of those 4 nodes one has RAM upgraded to 10GB and it also acts as name node and task tracker / resource manager. Later I will probably add separate host for those services.
I have also executed some MR v1 jobs. Terasort test for 100 000 000 records (~10GB) takes 25 mintes to finish, but I will include more detailed benchmarks when the cluster becomes fully operational.