[kudu-CR] KUDU-2975: Spread WAL across multiple directories

["Andrew Wong (Code Review)" <ge...@cloudera.org>]

Andrew Wong has uploaded a new patch set (#7) to the change originally created by YangSong. ( http://gerrit.cloudera.org:8080/14920 )

Change subject: KUDU-2975: Spread WAL across multiple directories
......................................................................

KUDU-2975: Spread WAL across multiple directories

Add a new gflag named "fs_wal_dirs" to support spreading WAL across
multiple directories.

Use a new class named "WalDirManager" to manage the WAL dirs. Every WAL
directory has an UUID, We record the directory's UUID and all
directories's UUIDs into a file named "wal_manager_instance". We also record
the tablet's WAL directory UUID into the tablet's metadata. We determine the
tablet WAL location based on the dir UUID recorded in metadata at
reboot.

// TODO: fix this
If switch 'fs_wal_dir' to 'fs_wal_dirs', first we need use "kudu fs
update_dirs" tool to update the WAL dir. We should make sure that the
new configuration includes the old ones, otherwise some tablets may be
failed after startup.

Because the tablet's metadata in old version had no WAL directory, we
look for the tablet's WAL directory under all the new WAL directories.
If found, we write the tablet's WAL into WalDirManager. We'll first
register the WAL directory in memory, and the next time the metadata is
flushed, the UUID is persisted to disk.

In this version, one of the WAL directorys's structure looks like this:
  wal_root
  +--instance
  +--wals
     +--wal_manager_instance
     +--tablet1_uuid
        +--index.0
        +--wal.0
     +--tablet2_uuid
        +--index.0
        +--wal.0

Some WAL directories are allowed to be missing at startup. Or some disks
that hold WAL are allowed to be failed at startup. If the tablets
located on failed WAL directories, they can be recovered by master.

Change-Id: Ic3490b2bbc0544e7c8a5f987fb83855ff155ac2c
---
M docs/administration.adoc
M src/kudu/consensus/consensus_peers-test.cc
M src/kudu/consensus/consensus_queue-test.cc
M src/kudu/consensus/log-test-base.h
M src/kudu/consensus/log.cc
M src/kudu/consensus/log.h
M src/kudu/consensus/log_cache-test.cc
M src/kudu/consensus/log_reader.cc
M src/kudu/consensus/raft_consensus_quorum-test.cc
M src/kudu/fs/CMakeLists.txt
M src/kudu/fs/fs.proto
M src/kudu/fs/fs_manager-test.cc
M src/kudu/fs/fs_manager.cc
M src/kudu/fs/fs_manager.h
M src/kudu/fs/fs_report.cc
M src/kudu/fs/fs_report.h
A src/kudu/fs/wal_dirs-test.cc
A src/kudu/fs/wal_dirs.cc
A src/kudu/fs/wal_dirs.h
M src/kudu/integration-tests/mini_cluster_fs_inspector.cc
M src/kudu/integration-tests/mini_cluster_fs_inspector.h
M src/kudu/integration-tests/multidir_cluster-itest.cc
M src/kudu/integration-tests/open-readonly-fs-itest.cc
M src/kudu/integration-tests/raft_consensus-itest.cc
M src/kudu/integration-tests/tablet_copy-itest.cc
M src/kudu/integration-tests/ts_recovery-itest.cc
M src/kudu/master/mini_master-test.cc
M src/kudu/master/mini_master.cc
M src/kudu/mini-cluster/external_mini_cluster.cc
M src/kudu/mini-cluster/external_mini_cluster.h
M src/kudu/mini-cluster/internal_mini_cluster.cc
M src/kudu/mini-cluster/internal_mini_cluster.h
M src/kudu/mini-cluster/mini_cluster.h
M src/kudu/server/server_base.cc
M src/kudu/tablet/metadata.proto
M src/kudu/tablet/tablet_bootstrap-test.cc
M src/kudu/tablet/tablet_bootstrap.cc
M src/kudu/tablet/tablet_metadata-test.cc
M src/kudu/tablet/tablet_metadata.cc
M src/kudu/tools/kudu-tool-test.cc
M src/kudu/tools/tool_action_fs.cc
M src/kudu/tools/tool_action_local_replica.cc
M src/kudu/tserver/mini_tablet_server-test.cc
M src/kudu/tserver/mini_tablet_server.cc
M src/kudu/tserver/mini_tablet_server.h
M src/kudu/tserver/tablet_copy-test-base.h
M src/kudu/tserver/tablet_copy_client-test.cc
M src/kudu/tserver/tablet_copy_client.cc
M src/kudu/tserver/tablet_server-stress-test.cc
M src/kudu/tserver/tablet_server-test-base.cc
M src/kudu/tserver/tablet_server-test-base.h
M src/kudu/tserver/tablet_server-test.cc
M src/kudu/tserver/ts_tablet_manager.cc
M src/kudu/util/env_util.cc
M src/kudu/util/env_util.h
55 files changed, 2,754 insertions(+), 297 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/20/14920/7
-- 
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ic3490b2bbc0544e7c8a5f987fb83855ff155ac2c
Gerrit-Change-Number: 14920
Gerrit-PatchSet: 7
Gerrit-Owner: YangSong <sy...@yeah.net>
Gerrit-Reviewer: Andrew Wong <aw...@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins (120)
Gerrit-Reviewer: Tidy Bot (241)
Gerrit-Reviewer: YangSong <sy...@yeah.net>