Changes between Version 25 and Version 26 of Tutorial/DataMgt
- Timestamp:
- Sep 24, 2010, 12:22:19 PM (14 years ago)
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Tutorial/DataMgt
v25 v26 55 55 The ''File Catalog'' service (also known as ''replica catalog'') in gLite is implemented using LFC. LFC service has a client implemented through commands whose names start with `lfc-`. These commands are installed on every UI and WN. 56 56 57 These LFC commands are seldom used: LFC interaction is normally done with commands handling the necessary interactions with both LFC and SE services to implement actual file management (mainly the so-called ''lcg_utils'' commands whose names start with `lcg-`.). There is one exception, `lfc-mkdir`, that '''must be used to create directories''' before creating LFN in them (`lfc-mkdir` supports a `-p` option to create parent directories, similar to the same option in Unix `mkdir`).57 These LFC commands are seldom used: LFC interaction is normally done with commands handling the necessary interactions with both LFC and SE services to implement actual file management (mainly the so-called ''lcg_utils'' commands whose names start with `lcg-`.). There is one exception, `lfc-mkdir`, that can be used to create empty directories. The lcg-xxx commands will create missing directories, but cannot create an empty directory. The command `lfc-mkdir` supports a `-p` option to create parent directories, similar to the same option in Unix `mkdir`. 58 58 59 59 All of these commands require a valid VOMS proxy with a valid VOMS extension (use `voms-proxy-init --voms`), else you need to use option `--vo` with `lcg-xxx` commands. `lcg-xxx` commands locate the LFC server from the VO used. To use a LFC server other than the default (central) one or with `lfc-xxx` commands, define environment variable `LFC_HOST` to the host name of the LFC server to use. … … 65 65 The main LFC commands that may be used under normal circumstances are: 66 66 * `lfc-mkdir [-]`: create a directory in LFC and optionally its parents. 67 * `lf s-ls [-l]`: similar to Unix `ls` command. Gives the content of a directory and optionally detailed information in a Unix like format. User and group are the DN of the owner and the FQAN of the primary VOMS group.67 * `lfc-ls [-l]`: similar to Unix `ls` command. Gives the content of a directory and optionally detailed information in a Unix like format. User and group are the DN of the owner and the FQAN of the primary VOMS group. 68 68 * `lfc-getacl / lfc-setacl`: LFC namespace supports Posix-like ACLs. See the man page for more information on the syntax, in particular for `lfc-setacl`. A file name has one ACL but a directory has 2 different ACLs: the ACL controlling access to the directory and the default ACL applied to new files (new sub-directories inherit the parent ACL). 69 69 … … 73 73 In the job description, this is possible to describe the data available on the grid that the job need to access. Data files can be identified by a LFN, a GUID or a SURL. This description is taken into account by WMS to select the appropriate site: a CE will be selected only if one the file replica is on one of the ''close SE'' for the CE (this is a configuration information for each CE). Then the job can retrieve the list of files provided, the replicas used... with command `glite-brokerinfo` (available only on WNs). 74 74 75 To specify the grid files the job needs access to, it is necessary to add the 2 followinglines to the JDL:75 To specify the grid files the job needs access to, it is necessary to add the following two lines to the JDL: 76 76 {{{ 77 77 DataAccessProtocol ={ "gsiftp","rfio"}; … … 79 79 }}} 80 80 81 `DataAccessProtocol` is a list of transfer/access protocol that the job will use to access the data. The protocols in the example are the most common but other possibilities are `xroot`, `dcap`, `https`... There is no default and this clause is required if `InputData` is present.81 `DataAccessProtocol` is a list of transfer/access protocol that the job will use to access the data. The protocols in the example are the most common but other possibilities are `xroot`, `dcap`, and `https`. There is no default and this clause is required if `InputData` is present. 82 82 83 83 File names specified in `InputData` can be LFN, GUID or SURL. The standard syntax is used with the corresponding prefix `lfn:`, `guid:` or `srm:`. See [wiki:Tutorial/DataMgt#MainDataManagementCommands above].