User:Torben Rasmussen (NSC)/SweGrid old/Using national storage resources

Introduction

(UNDER DEVELOPMENT)

The SNIC national storage infrastructure is implemented using dCache, which is a distributed storage system presenting the user with a single filesystem view. The front-end host of the system is srm://srm.swegrid.se which is the machine presenting the filesystem for the user.

The system uses VOMS proxy certificates for authentication. Please see, VOMS Certificates , for information on how to generate a voms proxy certificate.

Copying files

Copying files to and from resources is accomplished using the arccp command. The command can handle many of existing protocols, such as: http, https, httpg, ftp, gsiftp, lfc, rls, srm.

Copying single files

Copying single files is accomplished in the same way as using the normal cp command as shown in the following example:

[jonas@localhost jonas2]$ arccp archive.tar.gz srm://srm.swegrid.se/ops/

Recursive copying

Recursive copying is accomplished using the --recursive option. The argument to the option determines the depth of the recursive copy.

[jonas@localhost swestore]$ arccp --recursive=3 jonas2/ srm://srm.swegrid.se/ops/jonas/jonas2/

Listing files

Listing files on a resources is done using the arcls command. In the simplest form the command just takes a URL as input and displays names and directories without any extra information as shown in the following example:

[jonas@localhost jonas2]$ arcls srm://srm.swegrid.se/ops/
motd.1
bla
generated
ops
motd.f343
GridFTP-1.0.20-linux.gtk.x86.zip
test23
test24
ronstestfile
ronstestfile3
testfile-put-1296854868-6468a2d5df07.txt

Additional information can be listed by adding the --long option.

[jonas@localhost swestore]$ arcls --long srm://srm.swegrid.se/ops
<Name> <Type> <Size> <Creation> <Validity> <CheckSum> <Latency>
motd.1 file 354 2008-06-05 12:28:23 (n/a) adler32:582d7718 NEARLINE
bla dir 512 2008-08-22 12:23:49 (n/a) (n/a) NEARLINE
generated dir 512 2008-11-17 15:07:39 (n/a) (n/a) NEARLINE
ops dir 512 2010-01-21 11:26:00 (n/a) (n/a) NEARLINE
motd.f343 file 436 2010-01-08 14:35:40 (n/a) adler32:0fed94f2 ONLINE
GridFTP-1.0.20-linux.gtk.x86.zip file 30479220 2011-03-09 09:49:20 (n/a) adler32:5c67686b ONLINE
test23 file 0 2011-03-04 09:44:44 (n/a) adler32:00000001 ONLINE
test24 file 0 2011-03-04 09:45:07 (n/a) adler32:00000001 ONLINE
ronstestfile file 4 2010-11-23 17:46:13 (n/a) adler32:03cd014b ONLINE
ronstestfile3 file 4 2010-11-23 17:49:07 (n/a) adler32:03cd014b ONLINE
testfile-put-1296854868-6468a2d5df07.txt file 20 2011-02-04 22:28:47 (n/a) adler32:1a400272 ONLINE

Metadatainformation on a specific file can be listed by specifying the -m or --metadata option. In the following example the metadata information of the test23 file is shown:

[jonas@localhost swestore]$ arcls --metadata srm://srm.swegrid.se/ops/test23
/ops/test23
accessperm:rw-r-----
checksum:adler32:00000001
ctime:2011-03-04 09:44:44
filestoragetype:PERMANENT
group:25001
latency:ONLINE
lifetimeassigned:PT1S
lifetimeleft:PT1S
mtime:2011-03-04 09:44:45
owner:25001
path:/ops/test23
size:0
spacetokens:
type:file

Creating directories

There are no command line tool yet for creating directories. This command will probably be added in a upcoming release. In the meantime the following procedure can be used:

[jonas@localhost swestore]$ mkdir mydir
[jonas@localhost swestore]$ touch mydir/dummyfile
[jonas@localhost swestore]$ arccp ./mydir/ srm://srm.swegrid.se/ops/mydir/
[jonas@localhost swestore]$ arcls srm://srm.swegrid.se/ops/mydir
dummyfile

The dummmy file can be removed using the arcrm command described in the following sections.

Removing files

[jonas@localhost swestore]$ arcrm srm://srm.swegrid.se/ops/mydir/dummyfile

Removing directories

To remove directories they have to be empty. To indicate a directory the URL should end with a /.

[jonas@localhost swestore]$ arcrm srm://srm.swegrid.se/ops/mydir/