Software compression includes options to compress data in the following entities:
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Client
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MediaAgent
The software compression settings are applicable only to the primary storage policy copy and not applicable to the secondary copies. The auxiliary copy operations follow the compression settings of the primary copy.
You can use the LZO compression scheme or the GZIP compression scheme.
LZO compression usually provides faster throughput than GZIP, but might result in slightly more data written on the disk. GZIP provides a better compression ratio, but uses more CPU cycles.
On Feature Release 11.20 and higher, new clients and MediaAgents use the LZO compression scheme by default. Existing clients (except VSA proxies) and MediaAgents continue to use GZIP compression scheme as the default. VSA proxies use LZO compression for storage policies created in V11 SP4 or later.
You can change the compression scheme on a client using an additional setting. For more information, see Configuring the Compression Scheme.
Client Compression
Client compression is useful if the client and MediaAgent reside on separate computers and the client must send its data using a network. Client compression reduces the network load since the data is compressed before it leaves the client.
When compression is configured on the client:
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The data is compressed on the client computer.
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The compressed data is then sent to the MediaAgent which is written to the storage media.
MediaAgent Compression
MediaAgent compression can be useful if the MediaAgent software resides on a computer that is more powerful than the client computer. Using software to compress data can be processor intensive. Consequently, you may want to use MediaAgent compression for client computers with limited processing power.
When compression is configured on the MediaAgent:
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The data is compressed on the MediaAgent.
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The compressed data is then sent from the MediaAgent to the storage media.
The data compressed on the MediaAgent during data protection, is decompressed on the client computer during the data recovery.
Replication Compression
Data being replicated can be compressed between the source and destination computers. When compression is enabled, data is compressed on the source computer, replicated across the network to the destination computer, and uncompressed on the destination computer, thereby reducing the network load.