Start CTA¶

Documentation should contain “Hello world” example:

That is how to migrate one files to tape and how to get it back. This should include:

declaration of a library in CTA catalogue
declaration of tape pools and a tape
puting file into EOS
checking that the file is there
list pending archives
see tape mounted (like castor “tpstat” command)
show the “m” bit to confirm the file is on tape
remove disk copy on EOS
retrieve file from tape
see tape mounted (like castor “tpstat” command)
show a disk copy of a file somewhere on disk (example: <FST server:/<FST path>/00000000/00000007)

Debugging Authentication Problems¶

Force the cta command line tool to use Kerberos authentication:

export XrdSecPROTOCOL=krb5,unix

Get debugging info if KDC authentication does not work:

export XrdSecDEBUG=1

Trying out some commands¶

Now CTA should be up and running and we can try out some commands from the cmdline directory:

$ cta-admin ll add -n IBMJD3 -m "IBM lib 3"
$ cta-admin tp add -n cms_raw_08 -p 15 -m "CMS raw"
$ cta-admin ta add -v G12345 -l IBMJD3 -t cms_raw_08 -c 10000 -m "Tape"
$ cta-admin sc add -n single -i 2 -c 1 -m "A single copy class"

Running `tapeserverd`¶

Tape labelling¶

Tapes can be labelled with the following commands (depends on the tape library and the tape drive types):

  $ echo "VOL1V31001                           CASTOR                                    3">label.file
  $ mtx -f /dev/smc load 1 0
  $ dd if=label.file of=/dev/nst0 bs=80 count=1
  $ mt -f /dev/nst0 rewind
  $ mtx -f /dev/smc unload 1 0

Preparing the CTA environment for migrations¶

The library and tapes need to be registered for the migrations (use appropriate names for your setup):

# create library
  $ cta-admin logicallibrary add --name VLSTK --comment "ctasystest"
# create tape pool
  $ cta-admin tapepool add --name ctasystest --partialtapesnumber 5 --encrypted false --comment "ctasystest"  
# add tape to the tapepool and library
  $ cta-admin tape add --logicallibrary VLSTK --tapepool ctasystest --capacity 1000000000 \
  --comment "ctasystest" --vid V31001 --disabled false --full false
# create storage class
  $ cta-admin storageclass add --instance root --name ctaStorageClass --copynb 1 --comment "ctasystest"
# create archive route
  $ cta-admin archiveroute add --instance root --storageclass ctaStorageClass --copynb 1 \
  --tapepool ctasystest --comment "ctasystest" 
# create mount policy
  $ cta-admin mountpolicy add --name root --archivepriority 1 --minarchiverequestage 1 \
  --retrievepriority 1 --minretrieverequestage 1 --maxdrivesallowed 1 --comment "ctasystest"  
# create requester mount rule
  $ cta-admin requestermountrule  add --instance root --name root --mountpolicy ctasystest \
  --comment "ctasystest"

Using CTA¶

Storing a file into tape¶

Copy a file in the data directory that has the cta frontend attributes:

eos cp /etc/bashrc /eos/users/test/
# Check drives are up
cta-admin dr ls
# Check archival queue
cta-admin sq
# Check file on-disk/on-tape status
eos ls -y /eos/users/test/

Once archival is finished, queues should be empty, drive should be Free, eos should show d1::t1 to indicate there is a disk copy and a tape copy.

Remove file from disk and restore it from tape¶

# Remove file from disk
eos stagerrm /eos/users/test/bashrc

If eos ls -y /eos/users/test/ is excuted, then eos should show d0::t1. This means the file is removed from disk but it's stored into tape. To restore it into the disk:

xrdfs root://devbox.cern.ch prepare -s /eos/users/test/bashrc

And executing eos ls -y /eos/users/test/, it should show d1::t1

Finally that file can be copied to the user pc:

eos cp /eos/users/test/bashrc ./bashrc.bckp

In this example it's copied with the .bckp extension to avoid override the existing bashrc file in home directory.