Data & Storage Services

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

DSS

XROOTD news

New releaseNew features

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS

Presentation Title - 2

New bundled release

• A new production release is available since a few days (vmss_1.7)– It contains the xrootd tag v20100115-1117

• Huge changelog available in the Savannah page• See the ‘download’ section• https://savannah.cern.ch/projects/xrootd

– Main items:• Data management• Refinements for the Virtual Mass Storage• 3rd party copy available by default• Space reporting in Monalisa

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS Data management

• Big improvements visible in the ‘xrd’ command line interface– Of course the server must support them– Cluster-wide ‘ls’ and ‘recursive ls’

• Now the output is what one should expect– Query space

• It gives an approximation of the used/free space managed by the cluster

• A correct one if each server mounts a disjoint set of disks

– If you mount the same NAS to more than one server it will report more.

Presentation Title - 3

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS SE cleanup

• Now, the actual content of an SE can be compared to the information in the AliEn catalogue– It’s a very heavy maintenance operation, worth

doing from time to time– From the SE side it’s easy. Just compute the

result of the recursive ls in ‘/’• You have to sync with Latchezar/Pablo about the

actions– It was performed on ALICE::CERN::SE

• 1hr 50m for 5-6Mfiles

Presentation Title - 4

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS Bundle refinements

• The VMSS is more mature– The native-XROOTD ALICE site federation

through the Global Redirector• Automatic fetch of absent files

– Much faster than before• Automatic reporting to ML of the space

information– See the ‘SE status’ page

• Automatic reporting to ML of the server version– Easy to spot old ones from now on

Presentation Title - 5

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS The 3rd party copy

• Same plugin as CASTOR (by A.Peters)• Authenticated “Push” mode for files

– Files are pushed directly server->server– The push is triggered by the command xrd3cp

• Not included in the server bundle– No config needed, it works out of the box

Presentation Title - 6

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS Mailing list

• There’s a new CERN-centric mailing list• Used for announces about tags/versions

– XROOTD-announce.cern.ch• Everybody is invited

– Not much traffic is foreseen

Presentation Title - 7

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS The Global redirector

• Remarkable stability, it never needs restarts• It will soon reach the first limit of 64 native xrootd

sites in the same federation– A solution for this is in development– Will allow the aggregation of up to 256 sites

• No need to touch it now– But a check about the sites’ list will be performed– Completely transparent

• Some sites need to be refurbished– Old versions, not supporting it very well– A few of them also look unstable– More news after the round of checks

Presentation Title - 8

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/

it

InternetServices

DSS Upgrade!

• Upgrading is highly recommended

• Usual steps, usual Alien Howto– http://alien.cern.ch/twiki/bin/view/AliEn/

HowToInstallXrootdNew

• Better not to copy the old system.cnf– Copy the (few) values manually

• Better not as root, do a parallel normal installation– In a parallel directory in the ‘xrootd’ user’s home– Stop the former, clean (eventually) stale ML-related processes– Start the new one

Presentation Title - 9