BackBox H4.00 User Manual

Product Description
17 BackBox H4.00 User Manual
Compression
Software compression is available for Windows File System Data Stores, through a
well-known algorithm that can be enabled in the Volume Group.
• ZLIB – better compression, that adds to the VTC CPU load
• The End-Of-Tape (EOT) indication is sent to the Guardian tape process when
the size of the compressed data reaches the maximum volume size defined in
the Volume Group.
• VTCs add metadata to the User data received from SCSI commands. This
metadata is included in the computed Storage size that is displayed in the
web application and used to compute a Compression ratio. Consequently the
reported ratio is a bit lower than a ratio computed only on the User data.
• Before choosing the final compression setting, it is suggested to experiment
with the options to determine which is more appropriate for your data.
• To determine if compression is advantageous for your environment, check the
following:
• The effective compression for different backup types and different
compression algorithms on the Web UI Volume list page.
• The global effective compression per Volume Group in the Volume Summary
page.
• The CPU usage in the VTC server, using the Windows performance monitor
tools. IMPORTANT: CPU saturation must be avoided in the VTC.
• The impact on throughput, as reported by the BackBox statistical report
(OBB018 obey file).
• If the Windows files are backed up to an Enterprise Backup Software, any
second compression executed in the back-end infrastructure will not be
effective.
• Notes:
• The compression setting can be changed any time, and will affect all volumes
in that Volume Group once they are re-written.
• IMPORTANT: When sending the virtual volumes to a data de-duplication
appliance (such as Data Domain), BackBox VTC compression should be
disabled. Failure to do so will result in poor de-duplication ratios (Data
Domain “Global Compression”.)
Encryption of virtual volumes
Tape volumes can be encrypted by the BackBox VTC software or by the storage
subsystem where the media is written by BackBox.
Encryption by BackBox software
Software encryption is available for Windows File System Data Stores and for all
NonStop systems supported by BackBox: G06.xx, H06.xx and J06.xx.