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diff --git a/doc/network_compression.md b/doc/network_compression.md deleted file mode 100644 index 7327591ef63..00000000000 --- a/doc/network_compression.md +++ /dev/null @@ -1,71 +0,0 @@ -#On-Wire Compression + Decompression - -The 'compression translator' compresses and decompresses data in-flight -between client and bricks. - -###Working -When a writev call occurs, the client compresses the data before sending it to -brick. On the brick, compressed data is decompressed. Similarly, when a readv -call occurs, the brick compresses the data before sending it to client. On the -client, the compressed data is decompressed. Thus, the amount of data sent over -the wire is minimized. Compression/Decompression is done using Zlib library. - -During normal operation, this is the format of data sent over wire: - -~~~ -<compressed-data> + trailer(8 bytes) -~~~ - -The trailer contains the CRC32 checksum and length of original uncompressed -data. This is used for validation. - -###Usage - -Turning on compression xlator: - -~~~ -gluster volume set <vol_name> network.compression on -~~~ - -###Configurable parameters (optional) - -**Compression level** -~~~ -gluster volume set <vol_name> network.compression.compression-level 8 -~~~ - -~~~ -0 : no compression -1 : best speed -9 : best compression --1 : default compression -~~~ - -**Minimum file size** - -~~~ -gluster volume set <vol_name> network.compression.min-size 50 -~~~ - -Data is compressed only when its size exceeds the above value in bytes. - -**Other paramaters** - -Other less frequently used parameters include `network.compression.mem-level` -and `network.compression.window-size`. More details can about these options -can be found by running `gluster volume set help` command. - -###Known Issues and Limitations - -* Compression translator cannot work with striped volumes. -* Mount point hangs when writing a file with write-behind xlator turned on. To -overcome this, turn off `performance.write-behind` entirely OR -set`performance.strict-write-ordering` to on. -* For glusterfs versions <= 3.5, compression traslator can ONLY work with pure -distribute volumes. This limitation is caused by AFR not being able to -propagate xdata. This issue has been fixed in glusterfs versions > 3.5 - -###TODO -Although zlib offers high compression ratio, it is very slow. We can make the -translator pluggable to add support for other compression methods such as -[lz4 compression](https://code.google.com/p/lz4/) |