PC2-FileSystems

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Introduction

The PC² provides three types of file systems:

  1. A shared file system located on an external filer. This file system is available on all clusters.
  2. Cluster local file systems. They provide fast accesss (normally realized by a parallel file system).
  3. Node local disks.

Based on this file systems, every user can access the following directories: home, group, PC²-scratch, cluster-scratch, node-scratch.

We provide environment variables which point to the different directories. They are set automatically. The following table gives an overview of the PC² file systems. They are explained in more detail below.

Environment
Variable
Source Purpose Initial
Quota
Backup
HOME Filer permanent, small data, per account 5GB Yes
PC2GROUPS Filer permanent, group related data, created on request 200GB Yes
PC2SW Filer, Cluster pre-installed software - -
PC2SCRATCH Cluster temporary, working data, per account. Not available on all systems (see below). - No
PC2WORK Filer temporary, working data, per account 1TB No
TMPDIR
CCS_TMPDIR
node local temporary, created by WLM - No

HOME: Home Directory

Files in this directory are accessible on all PC² systems and on all systems running in the university of paderborn. This filesystem is restrictively quoted regarding file space and number of inodes. I/O-intensive applications should not use HOME. For this purpose we provide PC2WORK and PC2SCRATCH. HOME is backed up in regular intervals.

PC2GROUPS: Group Directory

To allow working group specific collaboration, we can provide a central directory. Files in this directory are accessible on all PC² systems and on all systems running in the university of paderborn. This filesystem is restrictively quoted regarding file space. If you need such a directory, please contact us. PC2GROUPS is backed up in regular intervals.

PC2SW: Software Directory

This directory contains all pre-installed software for a system. It may be cluster local and/or PC² wide.

PC2WORK: PC² Wide Working Directory

For each user account we provide a directory on the Filer which is accessible on all PC² systems and on all systems running in the university of paderborn. It may be used for storage of temporary files. There will be no backup service in this directory.

PC2SCRATCH: Cluster Local Working Directory

For each user account we provide a directory on the cluster local file system, if available. It may be used for storage of temporary files. There will be no backup service in this directory. If no cluster local file system is available PC2SCRATCH points to PC2WORK

TMPDIR, CCS_TMPDIR: Node Local Directories for Jobs

When a job is allocated via the Work Load Manager (WLM), a temporary directory for the job is created on each affected node. It will be deleted by the WLM, after the job has terminated.

FAQs

Why do I have two home directories?

If you are member of the University of Paderborn, you have a Campus-home directory on the Campus-Storage. This directory is protected by Kerberos.

To allow long running jobs and to ease the handling of our systems, we provide a PC²-home directory which is also located on the Campus filer but not proteced by Kerberos tickets. There you can specify special settings and environments related to our systems.

Logging in on our frontends, will set your home-directory to the PC2²-home.

In your Campus-home, you will find a subdirectory named pc2. It points to the PC²-home directory.

Can I access the PC² file systems if I am not logged in on a frontend?

Yes, you may access the following directories: $HOME, $PC2GROUPS and $PC2WORK. They are exported via NFS and CIFS and therefore accessible from Windows, MAC, Linux, ...

If you are not located at the University of Paderborn, you first have to establish a VPN to get access to our network.

A detailed description on how to connect the PC² file systems, can be found here. Please change the used URL in the description to: \\fs-cifs.uni-paderborn.de\upb\departments\pc2

After successfully connected, you will find these directories:

groups
the group directories ($PC2GROUPS)
scratch
the PC² wide scratch directories ($PC2WORK)
software
the pre-installed software ($PC2SW)
user
the home directories ($HOME).

They are organized as follows: <first letter of login name>/<login name>. E.g. users/k/kel

I cannot access my Campus-Home on the cluster nodes, why?

Your Campus-home is protected by Kerberos, which implies manually Kerberos ticket prolongations. This would impact long running jobs. Since you can access the PC²-home, PC2GROUPS, and PC2WORK from everywhere, there is no need the other way around. See also the 2 questions above.

How can I see my current quota usage?

Just type df -h . in the related directory (e.g., your PC²-home). For more details refer to here.

How can I change the access rights (ACLs)?

Normally, there is no need to do this. However, if you are using Windows refer to here. Using Linux, you have to use:

nfs4_getfacl
to show the ACLs related to a directory or a file
nfs4_setfacl
to set the ACLs related to a directory or a file
nfs4_editfacl
to edit (opens a vi session) the ACLs related to a directory or a file

For detailed information, please refer to the man pages

How can I access/restore a removed/earlier version of a file?

The filer of the directories HOME and PC2GROUPS makes daily snapshots. The snapshots of the last 7 days can be used to restore removed or older versions of a file.

Linux

In each directory, there is a hidden directory named .snapshot.

You have to enter .snapshot to see its contents.

For example, assume you have lost data in the directory MY_LIFE_DEPENDS_ON. To restore them do the following:

[kel@fe ~]$ cd MY_LIFE_DEPENDS_ON
[kel@fe MY_LIFE_DEPENDS_ON]$ cd .snapshot
[kel@fe .snapshot]$ ls -l
drwxrwx--- 23 kel user 524 10. Nov 14:23 daily_pc2_snapshot_2015-01-10
drwxrwx--- 23 kel user 524 10. Nov 14:23 daily_pc2_snapshot_2015-01-11
drwxrwx--- 23 kel user 524 10. Nov 14:23 daily_pc2_snapshot_2015-01-12
drwxrwx--- 23 kel user 524 10. Nov 14:23 SIQ-8d653f0d930f3780f885dc030729badc-latest
drwxrwx--- 23 kel user 524 10. Nov 14:23 yesterday_pc2_backup

Search the file you want to restore an copy it to the old place or wherever you want.

Windows

Detailed information can be found here.

If you are not located at the University of Paderborn, you first have to establish a VPN to get access to our network.