shell-and-data-access.md

Shell access and data transfer

Interactive Login

The Anselm cluster is accessed by SSH protocol via login nodes login1 and login2 at address anselm.it4i.cz. The login nodes may be addressed specifically, by prepending the login node name to the address.

|Login address|Port|Protocol|Login node| |---|---| |anselm.it4i.cz|22|ssh|round-robin DNS record for login1 and login2| |login1.anselm.it4i.cz|22|ssh|login1| |login2.anselm.it4i.cz|22|ssh|login2|

The authentication is by the private key

!!! Note "Note" Please verify SSH fingerprints during the first logon. They are identical on all login nodes:

29:b3:f4:64:b0:73:f5:6f:a7:85:0f:e0:0d:be:76:bf (DSA)
d4:6f:5c:18:f4:3f:70:ef:bc:fc:cc:2b:fd:13:36:b7 (RSA)

Private key authentication:

On Linux or Mac, use

local $ ssh -i /path/to/id_rsa username@anselm.it4i.cz

If you see warning message "UNPROTECTED PRIVATE KEY FILE!", use this command to set lower permissions to private key file.

local $ chmod 600 /path/to/id_rsa

On Windows, use PuTTY ssh client.

After logging in, you will see the command prompt:

                                            _
                       /\                  | |
                      /  \   _ __  ___  ___| |_ __ ___
                     / /\ \ | '_ \/ __|/ _ \ | '_ ` _ \
                    / ____ \| | | \__ \  __/ | | | | | |
                   /_/    \_\_| |_|___/\___|_|_| |_| |_|


                        http://www.it4i.cz/?lang=en

Last login: Tue Jul  9 15:57:38 2013 from your-host.example.com
[username@login2.anselm ~]$

Example to the cluster login:

The environment is not shared between login nodes, except for shared filesystems.

Data Transfer

Data in and out of the system may be transferred by the scp and sftp protocols.  (Not available yet.) In case large volumes of data are transferred, use dedicated data mover node dm1.anselm.it4i.cz for increased performance.

|Address|Port|Protocol| |---|---| |anselm.it4i.cz|22|scp, sftp| |login1.anselm.it4i.cz|22|scp, sftp| |login2.anselm.it4i.cz|22|scp, sftp| |dm1.anselm.it4i.cz|22|scp, sftp|

The authentication is by the private key

!!! Note "Note" Data transfer rates up to 160MB/s can be achieved with scp or sftp.

1TB may be transferred in 1:50h.

To achieve 160MB/s transfer rates, the end user must be connected by 10G line all the way to IT4Innovations and use computer with fast processor for the transfer. Using Gigabit ethernet connection, up to 110MB/s may be expected.  Fast cipher (aes128-ctr) should be used.

!!! Note "Note" If you experience degraded data transfer performance, consult your local network provider.

On linux or Mac, use scp or sftp client to transfer the data to Anselm:

local $ scp -i /path/to/id_rsa my-local-file username@anselm.it4i.cz:directory/file

For example how to using scp command:

local $ scp -i /path/to/id_rsa -r my-local-dir username@anselm.it4i.cz:directory

or

local $ sftp -o IdentityFile=/path/to/id_rsa username@anselm.it4i.cz

For example how to using sftp command:

Very convenient way to transfer files in and out of the Anselm computer is via the fuse filesystem sshfs

local $ sshfs -o IdentityFile=/path/to/id_rsa username@anselm.it4i.cz:. mountpoint

Using sshfs, the users Anselm home directory will be mounted on your local computer, just like an external disk.

Learn more on ssh, scp and sshfs by reading the manpages

$ man ssh
$ man scp
$ man sshfs

On Windows, use WinSCP client to transfer the data. The win-sshfs client provides a way to mount the Anselm filesystems directly as an external disc.

More information about the shared file systems is available here.