CMS Tier-3 News Item
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
Details
dCache Upgrade
Because the several middlewares employed in the Grid are migrating towards a safer usage of the digital certificates based on the
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
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
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servers following the end of the downtime to avoid any error due to some outdated path to the new Grid commands.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
cms is going to become a secondary group, e.g.:
$ id dmeister
uid=571(dmeister) gid=532(ethz-higgs) groups=532(ethz-higgs),500(cms)
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]
. Please tell us if you will get issues there.
Following how the
/pnfs
will be modified by the partitioning:
$ ls -l /pnfs/psi.ch/cms/trivcat/store/user | grep -v cms
total 56
drwxr-xr-x 2 alschmid uniz-bphys 512 Feb 21 2013 alschmid
drwxr-xr-x 5 amarini ethz-ewk 512 Nov 7 15:37 amarini
drwxr-xr-x 18 andis ethz-bphys 512 Jan 5 2010 andis
drwxr-xr-x 2 arizzi ethz-bphys 512 Sep 16 17:49 arizzi
drwxr-xr-x 5 bean psi-bphys 512 Aug 24 2010 bean
drwxr-xr-x 5 bianchi ethz-higgs 512 Sep 9 09:40 bianchi
drwxr-xr-x 30 bmillanm uniz-bphys 512 Jan 17 2012 bmillanm
drwxr-xr-x 29 bortigno ethz-higgs 512 Apr 18 2013 bortigno
drwxr-xr-x 98 buchmann ethz-susy 512 Nov 5 20:36 buchmann
...
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
.pdf on the web, but it's pretty technical, the typical Grid user can safely skip these details.
kind regards,
Fabio Martinelli on behalf of the T3 Admins Team
FabioMartinelli 8. 11. 2013