Name¶
dccp - Copy a file from or to a dCache server.
Synopsis¶
dccp [option...] <sourceUrl> <destUrl>
Arguments¶
The following arguments are required:
sourceUrl
The URL of the source file.
destUrl
The URL of the destination file.
Description¶
The dccp utility provides a cp(1) like functionality on the dCache
file system. The source must be a single file while the destination could be
a directory name or a file name. If the directory is a destination, a new
file with the same name as the source name will be created there and the
contents of the source will be copied. If the final destination file exists
in dCache, it won’t be overwritten and an error code will be
returned. Files in regular file systems will always be overwritten if the -i
option is not specified. If the source and the final destination file are
located on a regular file system, the dccp utility can be used similar to
the cp(1) program.
Options¶
The following arguments are optional:
-a
Enable read-ahead functionality.
-b <bufferSize>
Set read-ahead buffer size. The default value is 1048570
Bytes. To disable the buffer this can be set to any value below the default.
dccp will attempt to allocate the buffer size so very large values should be
used with care.
-B <bufferSize>
Set buffer size. The size of the buffer is requested in
each request, larger buffers will be needed to saturate higher bandwidth
connections. The optimum value is network dependent. Too large a value will
lead to excessive memory usage, too small a value will lead to excessive
network communication.
-d <debug level>
Set the debug level. <debug level> is a integer
between 0 and 127. If the value is 0 then no output is generated, otherwise
the value is formed by adding together one or more of the following
values:
Value Enabled output
1 Error messages
2 Info messages
4 Timing information
8 Trace information
16 Show stack-trace
32 IO operations
32 IO operations
64 Thread information
-h <replyHostName>
Bind the callback connection to the specific hostname
interface.
-H
show progress during file transfer.
-i
Secure mode. Do not overwrite the existing files.
-l <location>
Set location for pre-stage. if the location is not
specified, the local host of the door will be used. This option must be used
with the -P option.
-p <first_port>:<last_port>
Bind the callback data connection to the specified TCP
port/rangeSet port range. Delimited by the ’:’ character, the
<first_port> is required but the <last_port> is optional.
-P
Pre-stage. Do not copy the file to a local host but make
sure the file is on disk on the dCache server.
-r <bufferSize>
TCP receive buffer size. The default is 256K. Setting to
0 uses the system default value. Memory useage will increase with higher
values, but performance better.
-s <bufferSize>
TCP send buffer size. The default is 256K. Setting to 0
uses the system default value.
-t <time>
Stage timeout in seconds. This option must be used with
the -P option.
Examples:¶
To copy a file to dCache:
To copy a file from dCache:
Pre-Stage request:
[user] $ dccp -P -t 3600 -l example.org
/acs/user_space/data_file
stdin:
[user] $ tar cf - data_dir | dccp -
/acs/user_space/data_arch.tar
stdout:
[user] $ dccp /acs/user_space/data_arch.tar - | tar xf
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