[2/3] kudu git commit: docs: add a note about RAID-0

[gr...@apache.org]

docs: add a note about RAID-0

Adds a note that a single RAID-0 device with multiple disks is not
preferable to specifying multiple fs directories across multiple disks.

Change-Id: Ibb17fae9459be04211bd0a7db6eca8e94e443f71
Reviewed-on: http://gerrit.cloudera.org:8080/11580
Reviewed-by: Adar Dembo <ad...@cloudera.com>
Tested-by: Kudu Jenkins


Project: http://git-wip-us.apache.org/repos/asf/kudu/repo
Commit: http://git-wip-us.apache.org/repos/asf/kudu/commit/fb79f8fc
Tree: http://git-wip-us.apache.org/repos/asf/kudu/tree/fb79f8fc
Diff: http://git-wip-us.apache.org/repos/asf/kudu/diff/fb79f8fc

Branch: refs/heads/master
Commit: fb79f8fccf6c6000f2569afb7fa2e41b02fdfe00
Parents: 75472c8
Author: Andrew Wong <aw...@cloudera.com>
Authored: Thu Oct 4 12:40:44 2018 -0700
Committer: Andrew Wong <aw...@cloudera.com>
Committed: Thu Oct 4 22:58:49 2018 +0000

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 docs/configuration.adoc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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http://git-wip-us.apache.org/repos/asf/kudu/blob/fb79f8fc/docs/configuration.adoc
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diff --git a/docs/configuration.adoc b/docs/configuration.adoc
index 6a0a7f0..ebc1636 100644
--- a/docs/configuration.adoc
+++ b/docs/configuration.adoc
@@ -74,7 +74,11 @@ the latency of Kudu writes.
 The `--fs_data_dirs` configuration indicates where Kudu will write its data
 blocks. This is a comma-separated list of directories; if multiple values are
 specified, data will be striped across the directories. If not specified, data
-blocks will be placed in the directory specified by `--fs_wal_dir`.
+blocks will be placed in the directory specified by `--fs_wal_dir`. Note that
+while a single data directory backed by a RAID-0 array will outperform a single
+data directory backed by a single storage device, it is better to let Kudu
+manage its own striping over multiple devices rather than delegating the
+striping to a RAID-0 array.
 
 Additionally, `--fs_wal_dir` and `--fs_metadata_dir` may be the same as _one
 of_ the directories listed in `--fs_data_dirs`, but must not be sub-directories