Data storage and data backup on the nesh

no/neinStudents yes/jaEmployees yes/jaFaculties no/neinstud. Unions

 

Content

 

Data storage and data backup on the nesh

Range of service

Backup of the user data in the home area of the nesh users. In addition, a further memory area is made available, which we call TAPE-CACHE. This is to store temporary data. Data in this storage area is moved to tape after a certain time.

Ihre Vorteile

The self-created data in the home area are secured. Every user can access the backups without having to contact the administrator.  Of course only read access to the backed up data is possible.

Availability

The service is available 24 hours a day in normal operation.

Service hours

on working days from 8-16

Contact

If you have any questions or problems, please contact Dr. Cebel Küçükkaraca or by telephone (Mon-Fri 9-16) at 880-1431.

Data management

The front-end computers and the NEC SX-ACE nodes jointly access a global file system with a total of 1.5 PB. A common HOME area and WORK area is available for all computers. On the vector computer system, the following file systems can be used by each user:

 

Variable Lifetime Data backup User Quota global o. lokal
$HOME as long as the account is active yes at the moment not yet global
$WORK as long as the account is active no no global
$TAPE_CACHE as long as the account is active no no locally on host computer nesh-fe

 

For long-term data storage on the NEC SX-ACE disks, users can access the $HOME home directory on the file system

/sfs/fs5/home-geomar  and  /sfs/fs6/home-sh.


If the entire space of the filesystem $HOME is occupied, then a login is no longer possible, running jobs will abort if additional disk space is required. In such cases, the computing centre will therefore take the necessary measures to maintain operation and - if necessary, after consulting with the responsible persons in the partner computing centres - delete jobs and user files.

The WORK areas ($WORK) are used for temporary storage of data. The WORK areas are not saved by the computing centre.

Filesystem $TAPE_CACHE

In addition to the globally available file systems $HOME, $WORK on the host 'nesh-fe', a local work area called $TAPE_CACHE is provided for storing data records that do not have to be accessed frequently. This area consists of a disk memory and a magnetic tape robot system that transfers files from the disk memory as soon as a capacity limit is exceeded while retaining all structural information. To avoid waiting times on the NEC SX node, the $TAPE_CACHE file system cannot be accessed directly from these computers. Data must be copied or transferred back from the $TAPE_CACHE file system to the globally available $HOME, $WORK file systems via the host 'nesh-fe'. (Note: A local batch queue called 'feque' was set up on the host 'nesh-fe0' for such tasks (see below).

The scope of the individual areas of work varies. The fastest area is $TMPDIR, followed by $WORK and finally $HOME. For fast access to data that is cached within a job, $TMPDIR should be used. Note, however, that $TMPDIR cannot be accessed after the job has finished. The lifetime of data on $WORK varies depending on the operational situation.

For temporary use the file system /tmp is available. On this filesystem a directory $TMPDIR is created with every login, which is deleted when logging out.

Since sufficient space on /tmp is essential for the system to function properly, files are deleted as soon as the free disk space is below a limit. All files that do not belong to an active job are therefore deleted when the limit value is exceeded.

For the definition of the terms Archiving, backup, migration and data storage.

Frequently asked questions (FAQ)

What is backed up?

A regular data backup is performed for the $HOME file system. All other user file systems including /tmp are currently N O T backed up. There is no list of files that have been deleted in the meantime.

When is the backup?

The backup is performed once a day.
 

How long are the backups kept?

The backups are kept for 8 weeks. A restore of files is possible for the last 2 weeks. Older file backups are only available in weekly intervals.
 

What to do if files are lost?

Every user can access his own backed up files in the directory /nfs/mybackup.
 

Notice

Filesystem $TAPE_CACHE:  A backup is not performed here, i.e. data deleted by mistake by the user cannot be restored. The backup of $TAPE_CACHE by the computer center does not replace the backup/archiving of the data by the user himself!

 

Artikelaktionen