BwHPC BPG Data Management

1 Local File Systems

In addition to computing capacity the bwHPC clusters are equipped with parallel file systems. For local data management it is important to differentiate if data is frequently used and persistent or quick access during a job's lifetime is desicive.

For each registered user a $HOME directory is provided in the parallel file system. A regular backup secures user's files stored in this directory. But quick access from compute nodes is not possible. For data that is read or written during a job's lifetime additional storage without backup is temporarily placed at the disposal. Since implementation varies between the bwHPC clusters, please visit the sites of bwUniCluster or bwForCluster JUSTUS for details.

Directory	Characteristics	Kind of Data
$HOME	with backup, limited, global file system	software packages, configuration files, important results, ...
Workspaces, $WORK, ...	quick access, limited, temporary, global file system	input/output files
$TMPDIR,$TMP	local file system, temporarily limited to batch job's lifetime	intermediate results

As a matter of principle, following rule should be observed: Do not compute in $HOME!

Disk space is like all HPC resources limited. If disk space is not sufficient, external storage services like SDS@hd can be used.

2 Data Transfer

Transfer of large files achieves higher throughput than transferring files of small size. It is recommended to collect files to a compressed archive file with tools like zip, tar, xz or others before transfer.

2.1 Transfer Tools

Type	Software	Remark	Executable on				Data transfer from/to
			Local°	bwUniCluster	bwForCluster	www	bwHPC cluster	SDS@hd
Command line tool	scp	Throughput < 150 MB/s (depending on cipher)	+	+	+		+
	sftp		+	+	+		+	+
	rsync		+	+	+		+
	rdata	Throughput to 350-400 MB/s		+				+
	wget	Download only	+	+	+	+
Client	WinSCP	based on SCP/SFTP, Windows only	+				+	+
	FileZilla	based on SFTP	+				+	+

° Depending on workstation's OS.

2.2 Hosts

System	Host
bwUniCluster	uc1.scc.kit.edu
bwForCluster JUSTUS	justus.uni-ulm.de
bwForCluster MLS&WISO Production	bwfor.cluster.uni-mannheim.de
bwForCluster MLS&WISO Production	bwforcluster.bwservices.uni-heidelberg.de