This part explains the syntax of calling the executable that
supports STORE FILE, FETCH
FILE and REMOVE FILE
operations.
put <pnfsID> <filename> -si=<storage-information> [<other-options>...]
get <pnfsID> <filename> -si=<storage-information> -uri=<storage-uri> [<other-options>...]
remove -uri=<storage-uri> [<other-options>...]
executable, after the
file was written to tertiary storage. In order to get the
file back from the TSS the information of the URI is
preferred over the information in the
<storage-information>.
executable>.
The <storage-information> is a string in the format
-si=size=<bytes>;new=<true/false>;stored=<true/false>;sClass=<StorageClass>;\ cClass0<CacheClass>;hsm=<StorageType>;<key>=<value>;[<key>=<value>;[...]]
Example:
-si=size=1048576000;new=true;stored=false;sClass=desy:cms-sc3;cClass=-;hsm=osm;Host=desy;
Mandatory storage information’s keys
poolmanager for pool attraction.
poolmanager for pool
attraction. May be '-'.
OSM specific storage information’s keys
Enstore specific storage information’s keys
There might be more key values pairs which are used by the
dCache internally and which should not affect the
behaviour of the executable.
The <storage-uri> is formatted as follows:
hsmType://hsmInstance/?store=<storename>&group=<groupname>&bfid=<bfid>
executable.
Example:
A storage-uri:
osm://osm/?store=sql&group=chimera&bfid=3434.0.994.1188400818542| Return Code | Meaning | Behaviour for PUT FILE | Behaviour for GET FILE |
|---|---|---|---|
| 30 <= rc < 40 | User defined | Deactivates request |
Reports problem to poolmanager
|
| 41 | No space left on device | Pool retries |
Disables pool and reports problem to poolmanager
|
| 42 | Disk read I/O error | Pool retries |
Disables pool and reports problem to poolmanager
|
| 43 | Disk write I/O error | Pool retries |
Disables pool and reports problem to poolmanager
|
| other | - | Pool retries |
Reports problem to poolmanager
|
Whenever a disk file needs to be copied to a Tertiary Storage
System dCache automatically launches an executable on the
pool containing the file to be copied. Exactly one instance
of the executable is started for each file. Multiple
instances of the executable may run concurrently for
different files. The maximum number of concurrent instances of
the executablesexecutable can be configured in the ’setup’
file of the pool as described in the section called “The pool ’setup’ file”.
The following arguments are given to the executable of a
STORE FILE operation on startup.
put <pnfsID> <filename> -si=<storage-information> <more options>
Details on the meaning of certain arguments are described in the section called “Summary of command line options”.
With the arguments provided the executable is supposed to
copy the file into the Tertiary Storage System. The
executable must not terminate before the transfer of the
file was either successful or failed.
Success must be indicated by a 0 return of
the executable. All non-zero values are interpreted as a
failure which means, dCache assumes that the file has not
been copied to tape.
In case of a 0 return code the executable
has to return a valid storage URI to dCache in formate:
hsmType://hsmInstance/?store=<storename>&group=<groupname>&bfid=<bfid>Details on the meaning of certain parameters are described above.
The <bfid> can either be provided by
the TSS as result of the STORE FILE
operation or the pnfsID may be used. The
latter assumes that the file has to be stored with exactly
that pnfsID within the TSS. Whatever URI
is chosen, it must allow to uniquely identify the file within
the Tertiary Storage System.
Only the URI must be printed to stdout by the
executable. Additional information printed either before
or after the URI will result in an error. stderr can be used
for additional debug information or error messages.
Whenever a disk file needs to be restored from a Tertiary
Storage System dCache automatically launches an
executable on the pool containing the file to be
copied. Exactly one instance of the executable is started
for each file. Multiple instances of the executable may run
concurrently for different files. The maximum number of
concurrent instances of the executable per pool as well as
the full path of the executable can be configured in the
’setup’ file of the pool as described in the section called “The pool ’setup’ file”.
The following arguments are given to the executable of a
FETCH FILE operation on startup:
get <pnfsID> <filename> -si=<storage-information> -uri=<storage-uri> <more options>
Details on the meaning of certain arguments are described in the section called “Summary of command line options”. For return codes see the section called “Summary of return codes”.
Whenever a file is removed from the dCache namespace (file
system) a process inside dCache makes sure that all copies
of the file are removed from all internal and external
media. The pool which is connected to the TSS which stores
the file is activating the executable with
the following command line options:
remove -uri=<storage-uri> <more options>
Details on the meaning of certain arguments are described in the section called “Summary of command line options”. For return codes see the section called “Summary of return codes”.
The executable is supposed to remove the
file from the TSS and report a zero return code. If a
non-zero error code is returned, the dCache will call the
script again at a later point in time.