GSI Linux filesystems

Home file systems

For personal data like source code, analysis tools ...
  • All home file systems are backed up daily
  • Space is limited: Do not store mass data (e.g. output of simulations, experiment data) in the home file system
  • A graphical tool for displaying the biggest files and directories is filelight (see TipsTrash also).

/u/

  • Central user home file system on dedicated file servers with fast disks and RAID protection
  • Capacity of 42 GB per user
  • This system is shared among all users.
  • Misuse is a kind of a denial of service attack! The following conditions will be regarded as misuse:
    • Your data occupies more than 50 GByte for more than 7 days or
    • Your data occupies more than 55 GByte
  • If your account causes a denial of service attack:
    • The volume of your user home directory will be write protected by an automatic procedure
    • To reenable you account after a denial of service attack you have to guarantee that you are able to avoid such a situation

info When write access has been blocked, you cannot start a graphical session any more. To delete files and regain access by KDE or XFCE you have to
  • login via SSH or su if you still have access to another computer
  • or login to a text console (switch by pressing [Ctrl]+[Alt]+[F1] and back with [Ctrl]+[Alt]+[F7])

info Get the information about your disk quota on the command line:
  • use the following command: quota -sf /u/$USER
$USER is just an environment variable defined by the shell (used in Bash and Zsh). If for some reasons this variable is not defined you can just replace the $USER env variable with your username.

NOTE: do not use the df command to check your disk quota. It reports information about the disk utilization for the entire /u/ filesystem exported from our NFS servers and thus it is related to all the users belonging to the file servers and not only your disk quota.

Quota reports on the LX-Pool machines: Please note that due to security reasons it's not currently possible to get a quota report when logged in on the lx-pool machines.

Software file systems

Here, software is installed centrally to make it available to all users. This software is not available or distributed by DebianPackageManagement.

CVMFS

Starting from 2012, CvmFs is replacing /usr/local-Installations throughout the Linux farm.

Please check the web page for more information about it (installed software, usage, etc.).

Data file systems

Volumes for the mass data with a capacity of about 100 TB up to some PB
  • output of simulations
  • experiment data

Lustre (Hera and Nyx)

  • HPC file systems /hera, /lustre/nyx/
  • For experiment and simulation data
  • No automatic backup of the data is organised. Of course, you can archive data on the tape library manually.
  • For more information take a look at LustreFs and LustreFsOld.

/s/

  • Linux global scratch file system
  • files are not permanent but will be deleted periodically (see cleanup policy below)

/tmp/

  • local partition for storing temporary data
  • used by system processes, also available for local users
  • files are not permanent but will be deleted periodically (see cleanup policy below)

/data.local/

  • local partition for storing user data
  • not distributed to other hosts
  • no backup of content (will be lost in case of hard drive crashes)

Cleanup policy for files on /tmp and /s

Host File system Removal of files
all hosts /s 30 days after last access to file. A minimum of 20 % free space will be kept free (files with a timestamp smaller than 30 days (29, 28, ...) are removed
lxb..., lxi... /tmp 30 days after last access to file. A minimum of 20 % free space will be kept free (files with a timestamp smaller than 30 days (29, 28, ...) are removed
all other hosts /tmp A minimum of 20 % free space will be kept free (oldest files are removed)
all hosts /data.local none

Deprecated file systems

Data file systems /d/ (being phased out)

  • Linux data file systems on RAID systems on dedicated file servers
  • Large volumes able to handle experiment - and simulation data
  • Fileservers are bought by experiment collaborations, administration is done by the LinuxGroup, volumes are typically accessible as /d/groupnamesomenumber
  • No automatic backup of the data is organised. Of course, you can archive data on the tape library manually.
  • You share a volume with up to 100 users of your group. Parallel and concurrent read/write acesss will significantly slow down the I/O performance. Optimise your analysis to avoid parallel I/O with a high number of batch jobs writing on the same volume. Your colleagues will not be happy, if you bring down the I/O speed on your groups file server by writing to it with 500 batch jobs in parallel ...

Home file systems /misc/ (being phased out)

  • Distributed home file system on local computer
  • Your /misc/ home will be exported via NFS to the whole linux farm
  • Only people with linux desktop computer can participate in the distributed home file system
  • Space is limited to 20 GByte due to the limited capacity of the backup system.
  • Main advantage compared to the /u/system:
    • You are the only user on the disk. No other user can block you or share the disk access
    • Use the full speed of your disk without network bottleneck or concurrent access of other users.
  • Disadvantage
    • If the local disk fails, all data since the last backup are lost. You cannot continue to work until a new disk is built in and your data are restored from the backup.
    • You will not be able to login to any cluster node if your desktop PC is turned off/unavailable.

ALERT! Usage of this file system is deprecated, we will not create any new /misc file system. Existing /misc file systems will be moved to the central /u file servers.

Software file systems /usr/local (deprecated)

Contrary to its naming /usr/local/ is a volume mounted via NFS from a central server all over the LinuxFarm.

For an incomplete software list see SoftwareInUsrLocal.

ALERT! This file system is available only for machines with old Debian versions up to Squeeze. Machines running Debian Wheezy or later will use CVMFS instead.

-- ChristopherHuhn, ThomasRoth, WalterSchoen -- 2004 - 2016
Topic revision: r48 - 2017-07-10, StefanHaller