Release Notes

hp StorageWorks File System Extender Release Notes 19
4Limitations
This chapter lists known limitations of the current FSE release, and where appropriate, provides possible
solutions. It contains the following sections:
• Common limitations, page 19
• Linux-specific limitations, page 20
• Windows-specific limitations, page 23
Common limitations
FSE client–server connection limitation
The FSE implementation does not support a proxy server or a firewall between the FSE client and the FSE
server. The FSE implementation only works if there is a direct LAN connection with full-duplex transmission
between the FSE client and FSE server.
Similarly, connections between FSE Management Console client and FSE Management Console server
through a firewall are not supported.
Available media space calculation limitation
The fsemedium --list --volume command reports three statistics related to the used and free space
on the FSE medium volumes:
• Size: Amount of total space on an FSE medium volume in MB.
• Avail: Amount of free space on the medium volume in MB.
• Used: Percentage of used space on the medium volume.
As the Used parameter is increased in steps of 1%, and the Avail parameter is calculated from the Size
and Used parameters, the value of the Avail parameter is only updated if the percentage of used space
has been changed by at least 1%. This means, if the total size of the migrated files in an FSE migration job
does not exceed 1% of the total space on the medium volume, the value of the Avail parameter will not
change after the migration is complete.
Using third-party backup software for backing up the FSE implementation
The FSE implementation uses a proprietary backup tool for backing up its current state to tape media. It
does not support any third-party backup applications. Using such applications for backing up the FSE
implementation would cause several problems, including recall of the offline files (if used for backup of the
FSE clients) and potential inconsistency or data corruption of the FSE databases and system files (if used for
backup of the FSE server).
Therefore, you are advised not to install and use third-party backup applications on a system that hosts FSE
software.
Internet SCSI (iSCSI) not supported
FSE does not support devices that use the Internet SCSI (iSCSI) protocol for data transfer.
Configuring SAN environments to prevent potential data loss
Tape devices that are shared among several computers (as part of a SAN environment) may occasionally
rewind FSE tape media due to bus resets induced by one of the connected computers. Such events are
most often handled internally by a switch or bridge and do not reach Back End Agents (BEA) that manage
data transfer to the devices. In this case, the bus resets are not handled by FSE. These may cause data loss
on the FSE media involved, if they occur while the data is being transferred from the FSE disk buffer to the
media.