User's Manual

HP StorageWorks File System Extender Software user guide 281
In all other cases it will be assumed that the medium has already been verified by the previous operation.
CAUTION: Data might get written to the wrong medium if it is exchanged manually and if an operation
that sends medium change notification from SCSI subsystem to the FSE implementation has been
performed. It is therefore hazardous to set this variable to “no” or “false” and perform manual drive
operations later on.
Example
HSM_BEA_COMPRESSION
This variable controls whether FSE uses the data compression functionality of the supported LTO tape
drives. By default, this functionality is enabled and the data are written to the tape drives in the compressed
form. Note that use of compression may decrease the tape drive performance, but enables storage of
approximately twice as much data as with compression disabled. HP recommends that you leave
compression enabled.
Example
Debugging HSM file system filter
To see the messages or debug trace information that the HSM file system filter left among the kernel
messages, proceed as follows.
Linux specific
On an FSE client, to see the messages or debug trace information the HSM file system filter left among the
kernel messages, run the command:
You can also redirect the dmesg buffer to a file by performing the following:
1. Add the following lines to the file /etc/syslog.conf:
2. Restart the syslogd daemon:
The file /var/log/kernel will track the complete dmesg history.
NOTE: If HSM file system generates too many kernel messages, they may not all be tracked in the file and
some of them may be lost.
For more information on logging system messages, see the sysklogd man page.
Windows specific
To see these messages on an the FSE client, follow the steps below:
1. In Windows Control Panel, double-click Administrative Tools, and then double-click Event Viewer.
2. Click System Log and under the Source column look for hsmfs source.
Debugging FSE backup and restore processes
To debug FSE backup and restore processes, use the following procedure:
export HSM_BEA_VERIFY_HEADER=yes
export HSM_BEA_COMPRESSION=off
# dmesg | grep hsmfs
# Log all kernel messages to file
kern.* /var/log/kernel
# kill -HUP SyslogdProcessID