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Time to introduce our new high performance cluster greentail
, an Hewlett Packard HPC solution. If you want to read more about the details of the hardware, you can find it at Enternal Link. The reference for greentail
is because this cluster consumes 18-24% less power/cooling than the competing bids. The green tail refers to the Smooth Green Snake, which no surprise, has a green tail. External Link for more information.
In order to accommodate the new cluster, we have reduced the Blue Sky Studios cluster from 3 racks in production to a single rack. That rack contains nothing but 24 gb memory nodes offering just over 1.1 TB of memory across 46 nodes. Because the cluster is not power consumption friendly, it is our “on demand” cluster. If jobs are pending in the sole bss24
queue (offering 92 job slots), we will get notified and will power on more nodes. Or just email us. If it is not being used, we'll power down the nodes. The login node for this cluster is host sharptail (which can only be reached by first ssh into host petaltail or swallowtail, then ssh to sharptail).
There are no changes to the Dell cluster (petaltail/swallowtail). However be sure to read the home directory section below. It is important all users understand the impact of changes to come.
If we like the HP management tools, in the future we may ingest cluster petaltail/swallowtail and sharptail into greentail for a single point of access. Regardless of that move, the home directories will be served by greentail. That is a significant change. More details below.
As always, suggestions welcome.
The purchase of the HP hardware followed a fierce bidding round in which certain design aspects had to met.
During the scheduled power outage of December 28th, 2010, some benchmarks were performed on old and new clusters. To read about the details of all that, view this page.
In short using linpack (More about Linpack on wikipedia) here are the results. The results are dependent on the combination of total memory, total cores, and speed of processors.
The password, shadow and group files of host petaltail were used to populate greentail's equivalent files.
If you change your password, do it on all four hosts (petaltail, swallowtail, sharptail and greentail).
I know, a pain.
Within the directory /home/username/.ssh there is a file named authorized_keys. Within this file are your public SSH keys. Because your home directory contents are copied over to host greentail, you should be able to ssh from host petaltail or swallowtail to host greentail without a password prompt. If not, your keys are not set up properly.
You can also log in to host greentail directly (ssh username@greentail.wesleyan.edu
). From host greentail should be able to to ssh to host petaltail or swallowtail without a password prompt. If not, your keys are not set up properly.
To set up your ssh keys:
ssh-keygen -t rsa
Note: the software stack on host petaltail/swallowtail created ssh keys for you automatically upon your first login, so for most of you this is all set.
To test if your keys are set up right, simply ssh around the hosts petaltail, swallowtail and greentail.