diff options
| author | Erick Tryzelaar <idadesub@users.sourceforge.net> | 2009-07-10 17:23:28 +0000 |
|---|---|---|
| committer | Anand V. Avati <avati@dev.gluster.com> | 2009-07-16 00:37:59 -0700 |
| commit | e40e361126d7843f1141c1568c39a10f8510cf42 (patch) | |
| tree | 0b3595c3ab7e4c6a71de221213c5c36d0353c445 | |
| parent | f1313842a25d8d162db36ba8afb2a34b224f41ca (diff) | |
Add a random initial offset to the afr round robin index
This patch helps to distribute load across an afr cluster
when you have clients with the same access patterns, such
as in benchmarking or map-reduce. By randomly offsetting
the initial read_child_rr, clients should distribute reads
over the afr nodes on average.
A better solution could be to randomly shuffle the children
instead of chosing a different initial offset. This should
average the reads better across the nodes, but I'm not
sure if there are any other consequences to doing this.
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>
| -rw-r--r-- | xlators/cluster/afr/src/afr.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c index a94f92600..118e0fc3d 100644 --- a/xlators/cluster/afr/src/afr.c +++ b/xlators/cluster/afr/src/afr.c @@ -2494,6 +2494,9 @@ init (xlator_t *this) i++; } + /* Randomly pick the starting read child */ + priv->read_child_rr = random() % priv->child_count; + ret = 0; out: return ret; |