hscan - Scan clusters via RAPI and save node/instance data


hscan [-p] [–no-headers] [-d path ] cluster...

hscan –version


hscan is a tool for scanning clusters via RAPI and saving their data in the input format used by hbal(1) and hspace(1). It will also show a one-line score for each cluster scanned or, if desired, the cluster state as show by the -p option to the other tools.

For each cluster, one file named cluster**.data** will be generated holding the node and instance data. This file can then be used in hbal(1) or hspace(1) via the -t option. In case the cluster name contains slashes (as it can happen when the cluster is a fully-specified URL), these will be replaced with underscores.

The one-line output for each cluster will show the following:

The name of the cluster (or the IP address that was given, etc.)
The number of nodes in the cluster
The number of instances in the cluster
The number of nodes failing N+1
The number of instances living on N+1-failed nodes
Total memory in the cluster
Free memory in the cluster
Total disk in the cluster
Free disk space in the cluster
The score of the cluster, as would be reported by hbal(1) if run on the generated data files.

In case of errors while collecting data, all fields after the name of the cluster are replaced with the error display.

Note: this output format is not yet final so it should not be used for scripting yet.


The options that can be passed to the program are as follows:

-p, –print-nodes
Prints the node status for each cluster after the cluster’s one-line status display, in a format designed to allow the user to understand the node’s most important parameters. For details, see the man page for htools(1).
-d path
Save the node and instance data for each cluster under path, instead of the current directory.
-V, –version
Just show the program version and exit.


The exist status of the command will be zero, unless for some reason loading the input data failed fatally (e.g. wrong node or instance data).


The program does not check its input data for consistency, and aborts with cryptic errors messages in this case.


$ hscan cluster1
Name     Nodes  Inst BNode BInst  t_mem  f_mem t_disk f_disk      Score
cluster1     2     2     0     0   1008    652    255    253 0.24404762
$ ls -l cluster1.data
-rw-r--r-- 1 root root 364 2009-03-23 07:26 cluster1.data