From d7d3274c6f6cea46ad296fc6d1259ee9a4e9964f Mon Sep 17 00:00:00 2001
From: hchiramm <hchiramm@redhat.com>
Date: Tue, 4 Aug 2015 11:07:42 +0530
Subject: Adding Features and planning features to glusterfs-specs repo

As per the discussion (http://www.gluster.org/pipermail/gluster-users/2015-July/022918.html)
the specs are part of this repo.

Signed-off-by: hchiramm <hchiramm@redhat.com>
---
 .../Onwire Compression-Decompression.md            | 96 ++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 Feature Planning/GlusterFS 3.5/Onwire Compression-Decompression.md

(limited to 'Feature Planning/GlusterFS 3.5/Onwire Compression-Decompression.md')

diff --git a/Feature Planning/GlusterFS 3.5/Onwire Compression-Decompression.md b/Feature Planning/GlusterFS 3.5/Onwire Compression-Decompression.md
new file mode 100644
index 0000000..a26aa7a
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+++ b/Feature Planning/GlusterFS 3.5/Onwire Compression-Decompression.md	
@@ -0,0 +1,96 @@
+Feature
+=======
+
+On-Wire Compression/Decompression
+
+1. Summary
+==========
+
+Translator to compress/decompress data in flight between client and
+server.
+
+2. Owners
+=========
+
+-   Venky Shankar <vshankar@redhat.com>
+-   Prashanth Pai <ppai@redhat.com>
+
+3. Current Status
+=================
+
+Code has already been merged. Needs more testing.
+
+The [initial submission](http://review.gluster.org/3251) contained a
+`compress` option, which introduced [some
+confusion](https://bugzilla.redhat.com/1053670). [A correction has been
+sent](http://review.gluster.org/6765) to rename the user visible options
+to start with `network.compression`.
+
+TODO
+
+-   Make xlator pluggable to add support for other compression methods
+-   Add support for lz4 compression: <https://code.google.com/p/lz4/>
+
+4. Detailed Description
+=======================
+
+-   When a writev call occurs, the client compresses the data before
+    sending it to server. On the server, compressed data is
+    decompressed. Similarly, when a readv call occurs, the server
+    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.
+
+5. Usage
+========
+
+Turning on compression xlator:
+
+        # gluster volume set <vol_name> network.compression on
+
+Configurable options:
+
+        # gluster volume set <vol_name> network.compression.compression-level 8
+        # gluster volume set <vol_name> network.compression.min-size 50
+
+6. Benefits to GlusterFS
+========================
+
+Fewer bytes transferred over the network.
+
+7. Issues
+=========
+
+-   Issues with striped volumes. Compression xlator cannot work with
+    striped volumes
+
+-   Issues with write-behind: Mount point hangs when writing a file with
+    write-behind xlator turned on. To overcome this, turn off
+    write-behind entirely OR set "performance.strict-write-ordering" to
+    on.
+
+-   Issues with AFR: AFR v1 currently does not propagate xdata.
+    <https://bugzilla.redhat.com/show_bug.cgi?id=951800> This issue has
+    been resolved in AFR v2.
+
+8. Dependencies
+===============
+
+Zlib library
+
+9. Documentation
+================
+
+<http://review.gluster.org/#/c/7479/3/doc/network_compression.md>
+
+10. Status
+==========
+
+Code merged upstream.
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cgit