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Using fileservers

The Electron Microscope  Unit has several file servers - from the UCT-managed ResearchData storage, Frodo, a FreeBSD fileserver with 96Terabytes, and Athena - both a compute and storage server, with 96 Terabytes. Athena can be accessed remotely, just like frodo, but if using athena as a compute server, it can directly access its local storage under /data.

Frodo is a fileserver for EMU - with 96 Terabytes of storage.

It authenticates against the UCT LDAP server, so you will need your UCT ID and password to access it.

The steps below are all encapsulated in script, invoked by typing "frodo" on other machines within EMU. However, if you need to mount another machine, or wish to mount another directory, the instructions below should prove useful.

ssh access to Frodo

The recommended method of using it is via ssh - the secure shell on all our unix machines. This means you can log into it and look at the files directly, or mount it remotely using sshfs.

The most convenient way of using ssh is by means of keys.

A comprehensive discussion can be found on the Arch Wiki, but here is a quick start.

First of all, log in to frodo via ssh. If you don't specify a username with ssh, it will assume you have the same username as your current login. If the local username is different to your UCT ID number (perhaps because you are using your own laptop, you need to specify your UCT ID number (01234567 below in the examples).

Below, I presume you are using an EMU computer to access frodo, and the usernames are the same.

Otherwise, you will need you UCT ID before “@” before frodo in all lines below, like

ssh 01234567@frodoinstead of ssh frodo.

That said, let's do that :-

ssh frodo

Answer y to this question - you will not be prompted again.

The authenticity of host 'frodo (137.158.82.131)' can't be established.
ECDSA key fingerprint is SHA256:k4qmDAEmucSGKCSQejd9x6x/+yWsACE854Q2y/TMAAQ.
Are you sure you want to continue connecting (yes/no)?

Password:S3cr3t

[01234567@frodo ~]$

At this point, you are logged in to frodo, in your home directory /home/WF/01234567

This is not your data directory. The main RAID data storage is in a different place, at /data. please create your own, named, subdirectory there, as follows :-

mkdir /data/01234567

Of course, substitute your own UCT id here. Please put all your big files here, not in your home directory.

Now, log out.

exit

You are now back at your local computer. Let us make some ssh keys, so we do not have to type our password every time we access frodo.

New desktop - create ssh keys

If you move to a new computer, repeat all the steps below on that computer.

( usually, you can just type frodo to accomplish the steps below )

ssh-keygen

Press Enter, for the default filename, and the two passphrases.


Generating public/private rsa key pair.
Enter file in which to save the key (/home/01234567/.ssh/id_rsa):
Created directory '/home/01234567/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again: 
Your identification has been saved in /home/01234567/.ssh/id_rsa.
Your public key has been saved in /home/01234567/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256: sUayubP0q2BIFkkyAK9Z8gPZK3DCuFvxWk9OcFRdhjk 01234567@boxer2
The key's randomart image is:
+---[RSA 2048]----+
|B .   .... +o    |
|oB.  .    E.     |
|B.O.  o o  .     |
|.@o    = o       |
|B   o = S        |
|* =  = o         |
|.o  o *          |
|   . o +         |
|      o.o.       |
+----[SHA256]-----+

Now, copy the key over to frodo, like this :-

ssh-copy-id frodo

/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
Password:

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'frodo'"
and check to make sure that only the key(s) you wanted were added.

Enter your UCT password when prompted.

From your unix computer, you can now mount this data directory locally, and treat it as a part of your local file system. First, create the mount point.

mkdir frodo

Every time you log in to your desktop

Then, you can do the mount.

sshfs frodo:/data/01234567 frodo

Because you have set the keys up, it will not prompt you for a password. You can now use the files on frodo as if they are on your own computer - they will appear under the frodo directory you created above.