私は Plesk ボックス (onyx) 上で Roundcube Webmail クライアントを実行している MySQL サーバー (バージョン 5.1) を持っています。日中は数百人のユーザーがこのサーバーを利用しています。ハイパーバイザーの Virtuozzo は私たちと一日中この作業を行っており、コンテナー自体が膨大な量の I/O を生成していることを発見しました。
I/O が非常に高くなったため、サーバー全体がクラッシュし、ファイル システムが破損しました。
**
免責事項: 以下の SHOW は、mysql の停止/開始後に最新のものになります。
**
(Centos 6.9の場合)
仕様:
AMD Opteron(tm) Processor 6344
Core Name
Abu Dhabi
# of Cores
12-Core
# of Threads
12
Operating Frequency
2.6 GHz
Hyper Transports
6.40 GT/s
L2 Cache
6 x 2MB
L3 Cache
2 x 8MB
Manufacturing Tech
32 nm
30GB RAM (I have provided this to the container), server has 64 total.
私の my.cnf 構成は次のとおりです: (ごめんなさい、乱雑です。私たちの多くが一日中サーバーを稼働させようとしていたからです。必要に応じて整理してください。)
[mysqld]
local-infile=0
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
innodb_table_locks=0
#innodb_buffer_pool_size=10240M
#Add
innodb_buffer_pool_size=16G
thread_cache_size=20
tmp_table_size=256M
max_heap_table_size=256M
query_cache_size=0
query_cache_type=0
innodb_additional_mem_pool_size=32M
innodb_file_io_threads=8
innodb_stats_on_metadata=0
innodb_thread_concurrency=24
# Recommended. Also changed thread concurrency to 24 from 12
innodb_flush_log_at_trx_commit=0
key_buffer_size=64M
slow_query_log=1
slow_query_log_file=mysql-slow.log
long_query_time = 1
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
innodb_buffer_pool_size=2M
innodb_additional_mem_pool_size=500K
innodb_log_buffer_size=500K
innodb_thread_concurrency=2
[mysqld]
max_connections=2000
max_user_connections=0
より詳しい情報：
mysql> SHOW GLOBAL VARIABLES LIKE 'innodb_log_file_size';
+----------------------+---------+
| Variable_name | Value |
+----------------------+---------+
| innodb_log_file_size | 5242880 |
+----------------------+---------+
1 row in set (0.00 sec)
より詳しい情報：
mysql> SHOW GLOBAL STATUS;
+-----------------------------------+----------+
| Variable_name | Value |
+-----------------------------------+----------+
| Aborted_clients | 0 |
| Aborted_connects | 1 |
| Binlog_cache_disk_use | 0 |
| Binlog_cache_use | 0 |
| Bytes_received | 830216 |
| Bytes_sent | 39213368 |
| Com_admin_commands | 5 |
| Com_assign_to_keycache | 0 |
| Com_alter_db | 0 |
| Com_alter_db_upgrade | 0 |
| Com_alter_event | 0 |
| Com_alter_function | 0 |
| Com_alter_procedure | 0 |
| Com_alter_server | 0 |
| Com_alter_table | 0 |
| Com_alter_tablespace | 0 |
| Com_analyze | 0 |
| Com_backup_table | 0 |
| Com_begin | 0 |
| Com_binlog | 0 |
| Com_call_procedure | 0 |
| Com_change_db | 2 |
| Com_change_master | 0 |
| Com_check | 0 |
| Com_checksum | 0 |
| Com_commit | 0 |
| Com_create_db | 0 |
| Com_create_event | 0 |
| Com_create_function | 0 |
| Com_create_index | 0 |
| Com_create_procedure | 0 |
| Com_create_server | 0 |
| Com_create_table | 0 |
| Com_create_trigger | 0 |
| Com_create_udf | 0 |
| Com_create_user | 0 |
| Com_create_view | 0 |
| Com_dealloc_sql | 0 |
| Com_delete | 22 |
| Com_delete_multi | 0 |
| Com_do | 0 |
| Com_drop_db | 0 |
| Com_drop_event | 0 |
| Com_drop_function | 0 |
| Com_drop_index | 0 |
| Com_drop_procedure | 0 |
| Com_drop_server | 0 |
| Com_drop_table | 0 |
| Com_drop_trigger | 0 |
| Com_drop_user | 0 |
| Com_drop_view | 0 |
| Com_empty_query | 0 |
| Com_execute_sql | 0 |
| Com_flush | 0 |
| Com_grant | 0 |
| Com_ha_close | 0 |
| Com_ha_open | 0 |
| Com_ha_read | 0 |
| Com_help | 0 |
| Com_insert | 7 |
| Com_insert_select | 0 |
| Com_install_plugin | 0 |
| Com_kill | 0 |
| Com_load | 0 |
| Com_load_master_data | 0 |
| Com_load_master_table | 0 |
| Com_lock_tables | 0 |
| Com_optimize | 0 |
| Com_preload_keys | 0 |
| Com_prepare_sql | 0 |
| Com_purge | 0 |
| Com_purge_before_date | 0 |
| Com_release_savepoint | 0 |
| Com_rename_table | 0 |
| Com_rename_user | 0 |
| Com_repair | 0 |
| Com_replace | 0 |
| Com_replace_select | 0 |
| Com_reset | 0 |
| Com_restore_table | 0 |
| Com_revoke | 0 |
| Com_revoke_all | 0 |
| Com_rollback | 0 |
| Com_rollback_to_savepoint | 0 |
| Com_savepoint | 0 |
| Com_select | 4259 |
| Com_set_option | 1098 |
| Com_show_authors | 0 |
| Com_show_binlog_events | 0 |
| Com_show_binlogs | 0 |
| Com_show_charsets | 0 |
| Com_show_collations | 1 |
| Com_show_column_types | 0 |
| Com_show_contributors | 0 |
| Com_show_create_db | 0 |
| Com_show_create_event | 0 |
| Com_show_create_func | 0 |
| Com_show_create_proc | 0 |
| Com_show_create_table | 0 |
| Com_show_create_trigger | 0 |
| Com_show_databases | 3 |
| Com_show_engine_logs | 0 |
| Com_show_engine_mutex | 0 |
| Com_show_engine_status | 0 |
| Com_show_events | 0 |
| Com_show_errors | 0 |
| Com_show_fields | 449 |
| Com_show_function_status | 0 |
| Com_show_grants | 0 |
| Com_show_keys | 0 |
| Com_show_master_status | 0 |
| Com_show_new_master | 0 |
| Com_show_open_tables | 0 |
| Com_show_plugins | 0 |
| Com_show_privileges | 0 |
| Com_show_procedure_status | 0 |
| Com_show_processlist | 0 |
| Com_show_profile | 0 |
| Com_show_profiles | 0 |
| Com_show_slave_hosts | 0 |
| Com_show_slave_status | 0 |
| Com_show_status | 7 |
| Com_show_storage_engines | 0 |
| Com_show_table_status | 0 |
| Com_show_tables | 3 |
| Com_show_triggers | 0 |
| Com_show_variables | 9 |
| Com_show_warnings | 0 |
| Com_slave_start | 0 |
| Com_slave_stop | 0 |
| Com_stmt_close | 0 |
| Com_stmt_execute | 0 |
| Com_stmt_fetch | 0 |
| Com_stmt_prepare | 0 |
| Com_stmt_reprepare | 0 |
| Com_stmt_reset | 0 |
| Com_stmt_send_long_data | 0 |
| Com_truncate | 0 |
| Com_uninstall_plugin | 0 |
| Com_unlock_tables | 0 |
| Com_update | 26 |
| Com_update_multi | 0 |
| Com_xa_commit | 0 |
| Com_xa_end | 0 |
| Com_xa_prepare | 0 |
| Com_xa_recover | 0 |
| Com_xa_rollback | 0 |
| Com_xa_start | 0 |
| Compression | OFF |
| Connections | 1167 |
| Created_tmp_disk_tables | 16 |
| Created_tmp_files | 5 |
| Created_tmp_tables | 39 |
| Delayed_errors | 0 |
| Delayed_insert_threads | 0 |
| Delayed_writes | 0 |
| Flush_commands | 1 |
| Handler_commit | 4309 |
| Handler_delete | 2 |
| Handler_discover | 0 |
| Handler_prepare | 0 |
| Handler_read_first | 17 |
| Handler_read_key | 6473 |
| Handler_read_next | 26911 |
| Handler_read_prev | 0 |
| Handler_read_rnd | 1449 |
| Handler_read_rnd_next | 3241 |
| Handler_rollback | 0 |
| Handler_savepoint | 0 |
| Handler_savepoint_rollback | 0 |
| Handler_update | 24 |
| Handler_write | 2468 |
| Innodb_buffer_pool_pages_data | 3675 |
| Innodb_buffer_pool_pages_dirty | 0 |
| Innodb_buffer_pool_pages_flushed | 239 |
| Innodb_buffer_pool_pages_free | 1044849 |
| Innodb_buffer_pool_pages_misc | 52 |
| Innodb_buffer_pool_pages_total | 1048576 |
| Innodb_buffer_pool_read_ahead_rnd | 5 |
| Innodb_buffer_pool_read_ahead_seq | 0 |
| Innodb_buffer_pool_read_requests | 125478 |
| Innodb_buffer_pool_reads | 3403 |
| Innodb_buffer_pool_wait_free | 0 |
| Innodb_buffer_pool_write_requests | 545 |
| Innodb_data_fsyncs | 156 |
| Innodb_data_pending_fsyncs | 0 |
| Innodb_data_pending_reads | 0 |
| Innodb_data_pending_writes | 0 |
| Innodb_data_read | 62099456 |
| Innodb_data_reads | 3447 |
| Innodb_data_writes | 321 |
| Innodb_data_written | 8141824 |
| Innodb_dblwr_pages_written | 239 |
| Innodb_dblwr_writes | 38 |
| Innodb_log_waits | 0 |
| Innodb_log_write_requests | 575 |
| Innodb_log_writes | 53 |
| Innodb_os_log_fsyncs | 80 |
| Innodb_os_log_pending_fsyncs | 0 |
| Innodb_os_log_pending_writes | 0 |
| Innodb_os_log_written | 296448 |
| Innodb_page_size | 16384 |
| Innodb_pages_created | 18 |
| Innodb_pages_read | 3657 |
| Innodb_pages_written | 239 |
| Innodb_row_lock_current_waits | 0 |
| Innodb_row_lock_time | 0 |
| Innodb_row_lock_time_avg | 0 |
| Innodb_row_lock_time_max | 0 |
| Innodb_row_lock_waits | 0 |
| Innodb_rows_deleted | 2 |
| Innodb_rows_inserted | 7 |
| Innodb_rows_read | 32244 |
| Innodb_rows_updated | 24 |
| Key_blocks_not_flushed | 0 |
| Key_blocks_unused | 53585 |
| Key_blocks_used | 3 |
| Key_read_requests | 6 |
| Key_reads | 3 |
| Key_write_requests | 0 |
| Key_writes | 0 |
| Last_query_cost | 0.000000 |
| Max_used_connections | 16 |
| Not_flushed_delayed_rows | 0 |
| Open_files | 3 |
| Open_streams | 0 |
| Open_table_definitions | 241 |
| Open_tables | 64 |
| Opened_files | 365 |
| Opened_table_definitions | 241 |
| Opened_tables | 519 |
| Prepared_stmt_count | 0 |
| Qcache_free_blocks | 0 |
| Qcache_free_memory | 0 |
| Qcache_hits | 0 |
| Qcache_inserts | 0 |
| Qcache_lowmem_prunes | 0 |
| Qcache_not_cached | 0 |
| Qcache_queries_in_cache | 0 |
| Qcache_total_blocks | 0 |
| Queries | 7047 |
| Questions | 7047 |
| Rpl_status | NULL |
| Select_full_join | 0 |
| Select_full_range_join | 0 |
| Select_range | 995 |
| Select_range_check | 0 |
| Select_scan | 44 |
| Slave_open_temp_tables | 0 |
| Slave_retried_transactions | 0 |
| Slave_running | OFF |
| Slow_launch_threads | 0 |
| Slow_queries | 31 |
| Sort_merge_passes | 0 |
| Sort_range | 31 |
| Sort_rows | 1449 |
| Sort_scan | 0 |
| Ssl_accept_renegotiates | 0 |
| Ssl_accepts | 0 |
| Ssl_callback_cache_hits | 0 |
| Ssl_cipher | |
| Ssl_cipher_list | |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_ctx_verify_depth | 0 |
| Ssl_ctx_verify_mode | 0 |
| Ssl_default_timeout | 0 |
| Ssl_finished_accepts | 0 |
| Ssl_finished_connects | 0 |
| Ssl_session_cache_hits | 0 |
| Ssl_session_cache_misses | 0 |
| Ssl_session_cache_mode | NONE |
| Ssl_session_cache_overflows | 0 |
| Ssl_session_cache_size | 0 |
| Ssl_session_cache_timeouts | 0 |
| Ssl_sessions_reused | 0 |
| Ssl_used_session_cache_entries | 0 |
| Ssl_verify_depth | 0 |
| Ssl_verify_mode | 0 |
| Ssl_version | |
| Table_locks_immediate | 4331 |
| Table_locks_waited | 0 |
| Tc_log_max_pages_used | 0 |
| Tc_log_page_size | 0 |
| Tc_log_page_waits | 0 |
| Threads_cached | 12 |
| Threads_connected | 4 |
| Threads_created | 16 |
| Threads_running | 1 |
| Uptime | 405 |
| Uptime_since_flush_status | 405 |
+-----------------------------------+----------+
291 rows in set (0.01 sec)
と私グローバル変数あります
理由はわかりませんが、このコンテナからハイパーバイザーへの主要な I/O が発生しています。以下は、NewRelic からの情報です。
MYSQLTuner では、この問題発生時に mysql サービスが実行されている必要があることは理解していますが、my.cnf ファイルに変更を加えて再起動し、実行しました。以下に、新規サービスの停止/開始直後に実行された追加情報を示します。ただし、これは役に立たない可能性があることに注意してください。
編集：
サーバーを数時間実行した後、mysqltuner の出力は次のようになります。
繰り返しますが、私はデータベースのプロではないので、お手柔らかにお願いします :)
そこで質問なのですが、このひどい速度低下をどうしたら解決できるでしょうか。どこから始めたらよいのかわかりません。追加情報が必要な場合はお知らせください。皆さん、ありがとうございます!