(r8) T3News201310181218 < CmsTier3

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*CMS Tier-3 News Item*

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  # Use the attached form to define title and summary of this news item. The details you can fill in directly on this wiki page.
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---++ Summary

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---++ Details
---+++ dCache Upgrade
Because the several middlewares employed in the Grid are migrating towards a safer usage of the digital certificates based on the [[https://wiki.egi.eu/wiki/SHA-2_support_middleware_baseline][SHA-2]] digests, it was requested to upgrade the T3 dCache =/pnfs= middleware to a newer version that's also designed to manage this new kind of certificates; we're accordingly going to upgrade the T3 dCache =/pnfs= middleware from the current version =2.2= to version [[http://www.dcache.org/downloads/1.9/release-notes-2.6.shtml][2.6]] on *Friday, November 8th starting at 12:00 until the end of the day*. During that time interval the T3 dCache =/pnfs= middleware will be either not available or unreliable so please avoid to access it.

---+++ UIs middleware upgrade
We are also exploiting this downtime to upgrade the Grid middlewares installed on the =t3ui0[1-9]= servers to the latest [[http://repository.egi.eu/2013/09/12/emi-ui-3-0-2/][UMD3 UI]]; the T3 users will be able to login and to work on the =t3ui0[1-9]= servers but please don't use the Grid commands like =srmcp= or =lcg-cp= because they're going to be upgraded; it's advisable to logout and to login again into the =t3ui0[1-9]= servers following the end of the downtime to avoid any error due to some outdated path to the new Grid commands. Also, don't submit any job involving the T3 dCache =/pnfs= middleware.
---+++ New Linux Groups
An other visible change will be the partitioning of the T3 users in the Linux groups: 
   * =ethz-ecal=
   * =ethz-bphys=
   * =ethz-ewk=
   * =ethz-higgs=
   * =ethz-susy=
   * =psi-bphys=
   * =psi-pixel=
   * =uniz-phys=
   * =uniz-higgs=
   * =uniz-pixel= 
the former global primary group %GREEN%cms%ENDCOLOR% is going to become a secondary group, e.g.:
<pre>
$ id dmeister
uid=571(dmeister) gid=532(%BLUE%ethz-higgs%ENDCOLOR%) groups=532(%BLUE%ethz-higgs%ENDCOLOR%),500(%GREEN%cms%ENDCOLOR%)
</pre>
The partitioning of the T3 users in the Linux groups: 
   * will allow a faster and simpler understanding of the =/pnfs= space usage by leveraging on the new =gid= setting: having all the files assigned to =cms= always made this kind of accounting very tricky in dCache.
   * will allow to make accounting in the batch system also according to the new =gid= setting. 
   * as a side effect, each new file written in =/shome=, =/pnfs=, =/scratch=, =/tmp= will be written with the new =gid= setting and this will prevent users from an other group to accidentaly delete your group writeable files/dirs.
   * it will allow the creation of dedicated "group dirs" in =/pnfs= where only your group can operate.
conversely the partitioning is not suppose to alter your daily experiences on the servers =t3ui0[1-9]=, or on the computational servers =t3wn[10-40]=; kindly inform us if you will get issues there.

Following how the =/pnfs= will be modified by the partitioning:
<pre>
$ ls -l /pnfs/psi.ch/cms/trivcat/store/user | grep -v cms 
total 56
drwxr-xr-x    2 alschmid     %ORANGE%uniz-bphys%ENDCOLOR% 512 Feb 21  2013 alschmid
drwxr-xr-x    5 amarini      %RED%ethz-ewk%ENDCOLOR%   512 Nov  7 15:37 amarini
drwxr-xr-x   18 andis        %BROWN%ethz-bphys%ENDCOLOR% 512 Jan  5  2010 andis
drwxr-xr-x    2 arizzi       %BROWN%ethz-bphys%ENDCOLOR% 512 Sep 16 17:49 arizzi
drwxr-xr-x    5 bean         %TEAL%psi-bphys%ENDCOLOR%  512 Aug 24  2010 bean
drwxr-xr-x    5 bianchi      %BLUE%ethz-higgs%ENDCOLOR% 512 Sep  9 09:40 bianchi
drwxr-xr-x   30 bmillanm     %ORANGE%uniz-bphys%ENDCOLOR% 512 Jan 17  2012 bmillanm
drwxr-xr-x   29 bortigno     %BLUE%ethz-higgs%ENDCOLOR% 512 Apr 18  2013 bortigno
drwxr-xr-x   98 buchmann     %PURPLE%ethz-susy%ENDCOLOR%  512 Nov  5 20:36 buchmann
...
</pre>
---+++ Final Remarks
There won't be any email announcing the beginning of the downtime, but we will send the usual email announcing its successful completion.

If you have a good reason to postpone all those upgrades kindly let us know *asap* and we will find an other day; the Grid asked us to upgrade by the end of *30th November*.

If you're interested in the =SHA-2= topic there is a good [[http://www.eugridpma.org/documentation/hashrat/SHA1Risk.pdf][.pdf]] on the web, but it's pretty technical, the average CMS user can safely skip these details.




  

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%FORMFIELD{"User"}% %FORMFIELD{"Date"}%
T3NewsForm
Title	Scheduled downtime to upgrade dCache from version 2.2 to 2.6
Summary	On Friday 8th Nov at 12:00 we're going to upgrade dCache from version 2.2 to 2.6
User	FabioMartinelli
Date	8. 11. 2013