HowTo: Managing Tape File Families in dCache

File Families

• file_family is a dCache tag which determines the file family associated with all files in this directory.
• This is an Enstore specific flag.
• Files are grouped on Enstore tape volumes according to the storage group and + file family attribute. A file family is a name that defines a category, or family, of data files.
• Each experiment (i.e., each storage group) must carefully plan its set of file families.
• There may be many file families configured; by design there is no pre-set upper limit on the number.
• A given storage volume may only contain files belonging to one file family

Read File Family tag

• This can be done in dCache in 3 ways:

• Using the chimera command:

chimera readtag /pnfs/pic.es/data/atlas/ file_family

• Reading tags with dot commands:

cd /pnfs/pic.es/data/atlas/; grep "" $(cat ".(tags)()")

• Using Enstore commands:

. /usr/local/etc/setups.sh; cd /pnfs/pic.es/data/atlas/; enstore pnfs --tags 

Using a File Family in dCache

• In order to be able to use a new File Family (at least new for the dCache system) it is necessary to add it to the PoolManager configuration.
• There is a limited wildcard usage accepted by the PoolManger:

• At PIC some VOs are taking advantage of wildcards, so if you're just adding a new file family to the following storage groups you don't need to do any change at the dCache level:

- vo-dteam

- vo-magic

- vo-lhcb

- vo-cms

- vo-pau

- vo-cta

• For all other VOs / Storage Groups (i.e. vo-atlas) you need to login to the dccore.pic.es, edit /root/srm22/srm22-prod.xml, add/edit/remove the desired File Families and then propagate information using ./propagarCanvis.sh srm22-prod.xml -yes

• In the following example we're removing some File Families and adding a wildcard for some VOs (which will include the deleted File Families, so they will be still accepted by dCache):

[root@dccore01 ~]# cd /root/srm22

[root@dccore01 srm22]# vi srm22-prod.xml 

[root@dccore01 srm22]# ./propagarCanvis.sh srm22-prod.xml
diff /tmp/LinkGroupAuthorization.conf.temp /opt/d-cache/etc/LinkGroupAuthorization.conf

#############################################################################################

diff /tmp/PoolManager.conf.temp /opt/d-cache/config/PoolManager.conf
30,31c30,33
< psu create unit -store vo-pau\..+@enstore
< psu create unit -store vo-cta\..+@enstore
---
> psu create unit -store vo-pau.paus@enstore
> psu create unit -store vo-pau.mice@enstore
> psu create unit -store vo-pau.castor@enstore
> psu create unit -store vo-cta.cta@enstore
69c71,73
< psu addto ugroup ugroup-pau vo-pau\..+@enstore
---
> psu addto ugroup ugroup-pau vo-pau.paus@enstore
> psu addto ugroup ugroup-pau vo-pau.mice@enstore
> psu addto ugroup ugroup-pau vo-pau.castor@enstore
71c75
< psu addto ugroup ugroup-cta vo-cta\..+@enstore
---
> psu addto ugroup ugroup-cta vo-cta.cta@enstore

# Propagate changes with the '-yes' option

[root@dccore01 srm22]# ./propagarCanvis.sh srm22-prod.xml -yes
LinkGroupAuthorization.conf                                                                                                                                          100% 1011     1.0KB/s   00:00    
Per fer efectius els canvis fer un 'reload -yes' al PoolManager@dccore.pic.es i un 'update link groups' a SrmSpaceManager@srm.pic.es

• Finally you need to log to the PoolManager and to the SrmSpaceManager using SSH2 against the dCache Admin Console and execute reload -yes and update link groups respectively.