Limitations, Common limitations | HP File System Extender (FSE)

4 Limitations

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--volumecommand 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.

hp StorageWorks File System Extender Release Notes 19