HP StorageWorks Storage Mirroring Recover User's Guide (T5437-96008, November 2009)

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Compressing data for transmission
To help reduce the amount of bandwidth needed to transmit Storage Mirroring Recover
data, compression allows you to compress data prior to transmitting it across the
network. In a WAN environment this provides optimal use of your network resources. If
compression is enabled, the data is compressed before it is transmitted from the source.
When the target receives the compressed data, it decompresses it and then writes it to
disk. On a default Storage Mirroring Recover installation, compression is disabled.
Note:
Any replication sets from a source connected to the same IP address on a target
will share the same compression configuration.
Keep in mind that the process of compressing data impacts processor usage on the
source. If you notice an impact on performance while compression is enabled in your
environment, either adjust to a lower level of compression, or leave compression
disabled. Use the following guidelines to determine whether you should enable
compression:
● If data is being queued on the source at any time, consider enabling compression.
● If the server CPU utilization is averaging over 85%, be cautious about enabling
compression.
● The higher the level of compression, the higher the CPU utilization will be.
● Do not enable compression if most of the data is inherently compressed. Many
image (.jpg, .gif) and media (.wmv, .mp3, .mpg) files, for example, are already
compressed. Some images files, such as .bmp and .tif, are uncompressed, so
enabling compression would be beneficial for those types.
● Compression may improve performance even in high-bandwidth environments.
● Do not enable compression in conjunction with a WAN Accelerator. Use one or the
other to compress Storage Mirroring Recover data.
1. Right-click the connection on the right pane of the Replication Console and select
Connection Manager.
2. Select the Compression tab.