<> == Status == SL6 at Zeuthen is the default and recommended Linux version: * It has been the default operating system for all new systems for several years. * The complete compute farm, most workgroup servers and the majority of desktops are running it. * Users and groups are encouraged to request upgrading their remaining desktop and WGS systems A '''test system''' is available: A virtual machine with an alias name of '''sl6.zeuthen.desy.de''' has been set up with a WGS configuration. It is meant to be used for tests and development, not for running production jobs. === SL6 presentations === * [[http://www-zeuthen.desy.de/technisches_seminar/texte/SL6-20120110-2up.pdf|Technical Seminar, Zeuthen, 2012-01-10]] * [[https://indico.desy.de/getFile.py/access?contribId=3&resId=0&materialId=slides&confId=5707|DESY Linux Users Meeting, Hamburg, 2012-04-13]] == Changes w.r.t. SL5 from the user's point of view == === Enhancements === * SL6 makes use of more '''power saving''' features available in current hardware, resulting in significant savings especially on (partially) idle systems. This will not only reduce the institute's energy bill and help keeping the server rooms cool: Current desktop systems will also dissipate less heat and generate less noise. * '''sshfs''' is available on desktops and WGSs. If a filesystem is available on a WGS, but not on your desktop computer, running `mkdir /some/mount point; sshfs my-wgs:/some/filesystem /some/mount/point` will make it available. To unmount, run `fusermount -u /some/mount/point`. For details, please consult the sshfs(1) manpage. * On desktop systems, the local '''user can install additional software packages''' * '''GPU computing''' support - CUDA is installed on systems supporting it * GPGPU farm nodes with Tesla cards * the latest desktop model (for getting started, development, test) * '''VLC available''' as multimedia player * you have to install it on your own ( Gnome menu: System -> Administration -> Add/Remove Software ) * as the development process of multimedia libraries is incompatible with "Enterprise Linux Distributions" like SL6, VLC's availability is not guaranteed over SL6's lifetime - in case of security issues VLC will be removed from all systems * '''CVMFS''' access available on every desktop * configured repositories: *.cern.ch , *.desy.de , *.egi.eu , *.icecube.wisc.edu , *.opensciencegrid.org === General changes === * The '''default locale''' is now '''en_US.UTF-8''' * If you prefer the old default, or have trouble with UTF8, you can set `LANG=C` in `~/.i18n` . * UTF8 doesn't make things faster or use less memory. It may be a good idea to run jobs under LANG=C. * The '''AFS sysname list''' only goes back to SL4: `amd64_rhel60 amd64_rhel50 i586_rhel50 amd64_linux26 i386_linux26`. * Under '''/afs''', only the local cell shows up by default. * You can access other cells like `/afs/cern.ch` though. You just need to know they exist. * This prevents graphical file managers from digging through all foreign AFS cells. * The default '''PATH''' now has the directories `/usr/local/sbin:/usr/sbin:/sbin` appended * on SL6, the shell will find some commands it won't on SL5 or SL4 * '''KDE''' is not installed by default, and has received close to no testing. * '''GNOME''' is recommended. '''Ice``WM''' is available. * Users who absolutely must have KDE can install it on Desktops themselves * In GNOME, select System -> Administration -> Add/Remove Software, and installed the "KDE Desktop" package collection * kdepim (korganizer) is not available though, since the akonadi backend wouldn't work * The '''automounter''' is configured to mount only those file systems expected to be required on a system * Thus, on desktops, the automounter is not running at all because the NFSv3, pnfs and Lustre file systems it handles are not considered secure to export to desktops anyway. * A '''soft limit of 1024 user processes''' applies by default. This is an upstream change intended to prevent accidental fork bombs, which makes sense but may prevent a few legitimate and reasonable use cases. Since it's a soft limit, users can raise it if required (`ulimit -u 2048`). === Changes regarding software === * '''/opt/products''' is almost empty. Software installed there in the past is now preferably provided using the normal SL packages, or in /opt. * In many cases, there is no longer a '''default version''' if several releases of a software are installed. For example, instead of `maple`, run '`maple15` or `maple16`. Or use `ini`. But see the next item: * The (DESY specific) '''ini''' command is being replaced by the more standard '''module''' one from the [[http://modules.sourceforge.net/|Environment Modules]] project. In many cases, both ini and module can still be used, but module is the future. See [[Software_Env_with_Modules|Getting started with environment modules]]. * The '''spell checker''' is now '''hunspell''' and no longer aspell as on SL5 and ispell as on earlier SL releases. Unfortunately, an aspell command is available but is a useless stub, and an ispell command is available but is a compatibility wrapper script not working for all applications. Worst of all, a command `spell` is available too, and it's the useless aspell. * The Grid gLite user interface ('''ini glite''') is unsupported, please use the EMI-UI instead ('''source /project/grid/etc/profile.d/setup-grid-ui.sh'''). Further details can be found [[Grid/User_Info|here]]. == Limitations == * '''Only 64-bit''' systems are available. We still install all relevant 32-bit compatibility packages. * On '''desktops''', '''only''' the '''nogroup''' setup is supported. * No permanent storage (/usr1/scratch). Please use central storage instead, possibly from a WGS. The /tmp file system is of course available. Files there are deleted two weeks after they were last accessed. * '''No remote login'''. Please use your WGS instead. * Console login for any user, independent of group. * The '''local firewall''' is enabled, and all incoming ports closed by default. * This breaks qrsh on desktops. Please use it on a WGS instead. * Please let us know if you need additional ports opened for your work. === Software no longer provided === * '''ROOT''' * In 2011, DV/IT stopped providing new ROOT versions centrally and groups are expected to have their own installation tailored to their needs. This being said, there seem to be ROOT versions installed in /afs/desy.de/products/root . * '''CERNLIB''' (obsolete since 2000, native SL6 build no longer works correctly) * Users who still must use parts of cernlib can find the SL5 build in AFS. * For example, to use paw: ` env CERN=/afs/ifh.de/amd64_rhel50/products/cernlib /afs/ifh.de/amd64_rhel50/products/cernlib/2005/bin/paw` * This was tested only superficially, and if it doesn't work there's not much we can do about it. * The '''pine''' command has been an alias for '''alpine''' for half a decade, and is no longer available. Simply use `alpine` instead. * [[Adobe Reader Removal|Adobe Reader was removed for security]] == Known Problems == * emacs still uses spell instead of hunspell by default, although it's supposed to be fixed in the last update (which replaced our patched build) - great QA! * For some users, '''nedit''' reportedly crashes when run remotely. We are unable to reproduce this. Workaround: running {{{ XLIB_SKIP_ARGB_VISUALS=1 nedit }}} is reported to work for those users experiencing the problem. * The '''tcl/tk versions''' have changed, and there are '''no compatibility libraries''' available. Software linked against libtcl/libtk will have to be rebuilt. * If there is significant demand for it, such a compatibility package could be provided by -DV-.