glusterd: Introduce option to limit no. of muxed bricks per process

This commit introduces a new global option that can be set to limit
the number of multiplexed bricks in one process.

Usage:
`# gluster volume set all cluster.max-bricks-per-process <value>`

If this option is not set then multiplexing will happen for now
with no limitations set; i.e. a brick process will have as many
bricks multiplexed to it as possible. In other words the current
multiplexing behaviour won't change if this option isn't set to
any value.

This commit also introduces a brick process instance that contains
information about brick processes, like the number of bricks
handled by the process (which is 1 in non-multiplexing cases), list
of bricks, and port number which also serves as an unique identifier
for each brick process instance. The brick process list is
maintained in 'glusterd_conf_t'.

Updates: #151
Change-Id: Ib987d14ab0a4f6034dac01b73a4b2839f7b0b695
Signed-off-by: Samikshan Bairagya <samikshan@gmail.com>
Reviewed-on: https://review.gluster.org/17469
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-op-sm.c b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
index 9eba6025427..6b12d603728 100644
--- a/xlators/mgmt/glusterd/src/glusterd-op-sm.c
+++ b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
@@ -79,6 +79,10 @@ glusterd_all_vol_opts valid_all_vol_opts[] = {
          */
         { GLUSTERD_MAX_OP_VERSION_KEY,          "BUG_NO_MAX_OP_VERSION"},
         { GLUSTERD_BRICK_MULTIPLEX_KEY,         "disable"},
+        /* Set this value to 1 by default implying non-multiplexed behaviour.
+         * TBD: Discuss the default value for this. Maybe this should be a
+         * dynamic value depending on the memory specifications per node */
+        { GLUSTERD_BRICKMUX_LIMIT_KEY,          "1"},
         { NULL },
 };