PC2-FileSystems

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Introduction

The PC² provides three types of file systems:

  1. File systems located on an external filer. These file systems are available on all clusters (HOME, PC2DAT, and PC2SCRATCH).
  2. Cluster local file parallel file systems, providing fast accesss (PC2PFS).
  3. Node local disks.

All directories (except the HOME directory) are group based. 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
Contains Purpose Initial
Quota
Backup
HOME Absolute path to PC² wide home directory permanent, small data, per account 5GB Yes
PC2DATA Absolute path to the PC² wide group data directories permanent, data, per group Requested at project application Yes
PC2PFS Absolute path to a cluster local parallel file system (if available) temporary, scratch data, per group Requested at project application No
PC2SCRATCH Absolute path to PC² wide group scratch directories temporary, working data, per group Requested at project application No
PC2SW Absolute path to the PC² software directories pre-installed software, read only - -
TMPDIR
CCS_TMPDIR
Absolute path to node local disks temporary, created by WLM - No

HOME: Home Directory

This directory is 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 PC2PFS and PC2SCRATCH. HOME is backed up in regular intervals.

PC2DATA: PC² Wide Group Data Directories

For each project, we provide a directory to store persistent data. PC2DATA is accessible on all PC² systems and on all systems running in the University of Paderborn. It is restrictively quoted regarding file space and number of inodes. I/O- intensive applications should not use PC2DATA. For this purpose, we provide PC2PFS or PC2SCRATCH. PC2DATA is backed up in regular intervals.

PC2PFS: Cluster Local Parallel File System

If a cluster (e.g., OCuLUS) provides a parallel file system, then there will be a group directory for each project. There is no backup service.

PC2SCRATCH: PC2² Wide Group Scratch Directories

For each project, we provide a directory to store temporary data created by jobs running on the clusters. PC2SCRATCH is accessible on all PC² systems and on all systems running in the University of Paderborn. It is restrictively quoted regarding file space and number of inodes. There is no backup service. If a cluster provides a local parallel file system, you should this for job created data (refer to PC2PFS).

PC2SW: Software Directory

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

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 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, $PC2DATA, and $PC2SCRATCH. 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         for HOME and PC2DATA
 \\fs-cifs.uni-paderborn.de\upb\scratch\departments\pc2 for PC2SCRATCH

The home directories ($HOME) 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, PC2DATA, and PC2SCRATCH 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, PC2DATA, and PC2SCRATCH 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.

NOTE:You have to enter .snapshot to see its contents. An ls .snapshot will not show the 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.