80 Introduction to IBM Real-time Compression Appliances
8.4.1 Transparent mode
The transparent mode is the default in the software version 3.7. If you have a lot of NAS
resources at your NAS storage server that must not be compressed, such as data
compressed by an ECM application in many shares, and you want to compress only a part of
your NAS storage server, it is best to use the transparent mode.
To switch to the transparent mode, proceed as follows:
1. Set the option “Compress Mode” to disabled. Click System Option under the General
section and then click disabled in the row “Compress Mode” as shown in Figure 8-10.
Figure 8-10 Compress Mode Disabled, No New Compression Disabled
2. If you want to enable the “No New Compression” configuration capability, you have to set
the system option “No New Compression” to enable.
The option “No New Compression” unhides the drop-down box in the “Compression
Filters” menu under the Configuration section to switch on or off the condition that new
data will be written pass-through or compressed. Click System Options under the
General section and then click Enable in the row “No New Compression,” as you can see
in Figure 8-11.
Chapter 8. Administration 81
Figure 8-11 Compress Mode Disabled, No New Compression Enabled
The configuration of compression of shares/exports can be done on the “Compression
Filters” menu under the “Configuration” section, as shown in Figure 8-12 for CIFS and in
Figure 8-13 for NFS. You can see CLI examples in Example 8-2.
3. To create a new compressed share, select the share from the drop-down box or type the
UNC name of the share manually in the appropriate field and click Apply changes to
Shares/Exports. Additionally you can add some file extension in the field “Extension to
exclude” to avoid double compressing of compressed data.
The impact of the NNC switch is as follows:
– If you set the NNC option to “off”, all new data in the corresponding share/export will be
– If you set the NNC option to “on”, any new written data will not be compressed.
However, independently of the NNC switch, all existing data will not be changed.
4. To remove a compressed share/export from the filter list, mark the Delete check box of the
corresponding share/export and click Apply Changes to Shares/Exports.
Tip: If you delete a share/export from the list, all data will be unchanged and presented to
the clients directly without passing the compression engine. If the share/export contain
compressed data, you can only access them after manually recovery; see “Recovering
files when appliance is unavailable” on page 119.
82 Introduction to IBM Real-time Compression Appliances
Figure 8-12 Compression filters CIFS
Example 8-2 creating a compression filter for CIFS by command line
email@example.com> filter add bran1b -c nocheck -t cifs home
Transparent - - \\bran1b\C$
Transparent - - \\bran1b\D$
Transparent - - \\bran1b\E$
Transparent - - \\bran1b\ETC$
Transparent - - \\bran1b\F$
Transparent - - \\bran1b\HIDDEN$
Transparent - - \\bran1b\IPC$
Transparent - - \\bran1b\home
Tip: The column NNC is only displayed if the system option “No New Compression” is set