我们在VMWare上的CentOS 5.5上使用MySQL 5.0.77：
Linux dev.ic.soschildrensvillages.org.uk 2.6.18-194.11.4.el5PAE #1 SMP Tue Sep 21 05:48:23 EDT 2010 i686 i686 i386 GNU/Linux 我们最近从4GB RAM升级到8GB。 当我们这样做的时候，我们的mysqldump隔夜备份的时间从10分钟跳到了2个多小时。 由于数据库负载的原因，这也导致我们基于Plone的网站无响应。 转储使用优化的mysqldump格式，并通过套接字直接后台处理到另一台服务器。
任何想法，我们可以做什么来感激地解决。 MySQL升级会有帮助吗？ 我们可以做什么MySQLconfiguration？ 任何我们可以做的Linuxconfiguration？ 或者我们必须添加另一台服务器或转到64位？
我们在6GB PAE上运行了以前的（非虚拟）服务器，并没有注意到类似的问题。 这是在相同的MySQL版本，但Centos 4.4。
服务器configuration文件：
[mysqld] port=3307 socket=/tmp/mysql_live.sock wait_timeout=31536000 interactive_timeout=31536000 datadir=/var/mysql/live/data user=mysql max_connections = 200 max_allowed_packet = 64M table_cache = 2048 binlog_cache_size = 128K max_heap_table_size = 32M sort_buffer_size = 2M join_buffer_size = 2M lower_case_table_names = 1 innodb_data_file_path = ibdata1:10M:autoextend innodb_buffer_pool_size=1G innodb_log_file_size=300M innodb_log_buffer_size=8M innodb_flush_log_at_trx_commit=1 innodb_file_per_table [mysqldump] # Do not buffer the whole result set in memory before writing it to # file. Required for dumping very large tables quick max_allowed_packet = 64M [mysqld_safe] # Increase the amount of open files allowed per process. Warning: Make # sure you have set the global system limit high enough! The high value # is required for a large number of opened tables open-files-limit = 8192
服务器variables：
mysql> show variables; +---------------------------------+------------------------------------------------------------------+ | Variable_name | Value | +---------------------------------+------------------------------------------------------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /usr/local/mysql-5.0.77-linux-i686-glibc23/ | | binlog_cache_size | 131072 | | bulk_insert_buffer_size | 8388608 | | character_set_client | latin1 | | character_set_connection | latin1 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | latin1 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/local/mysql-5.0.77-linux-i686-glibc23/share/mysql/charsets/ | | collation_connection | latin1_swedish_ci | | collation_database | latin1_swedish_ci | | collation_server | latin1_swedish_ci | | completion_type | 0 | | concurrent_insert | 1 | | connect_timeout | 10 | | datadir | /var/mysql/live/data/ | | date_format | %Y-%m-%d | | datetime_format | %Y-%m-%d %H:%i:%s | | default_week_format | 0 | | delay_key_write | ON | | delayed_insert_limit | 100 | | delayed_insert_timeout | 300 | | delayed_queue_size | 1000 | | div_precision_increment | 4 | | keep_files_on_create | OFF | | engine_condition_pushdown | OFF | | expire_logs_days | 0 | | flush | OFF | | flush_time | 0 | | ft_boolean_syntax | + -><()~*:""&| | | ft_max_word_len | 84 | | ft_min_word_len | 4 | | ft_query_expansion_limit | 20 | | ft_stopword_file | (built-in) | | group_concat_max_len | 1024 | | have_archive | YES | | have_bdb | NO | | have_blackhole_engine | YES | | have_compress | YES | | have_crypt | YES | | have_csv | YES | | have_dynamic_loading | YES | | have_example_engine | NO | | have_federated_engine | YES | | have_geometry | YES | | have_innodb | YES | | have_isam | NO | | have_merge_engine | YES | | have_ndbcluster | DISABLED | | have_openssl | DISABLED | | have_ssl | DISABLED | | have_query_cache | YES | | have_raid | NO | | have_rtree_keys | YES | | have_symlink | YES | | hostname | app.ic.soschildrensvillages.org.uk | | init_connect | | | init_file | | | init_slave | | | innodb_additional_mem_pool_size | 1048576 | | innodb_autoextend_increment | 8 | | innodb_buffer_pool_awe_mem_mb | 0 | | innodb_buffer_pool_size | 1073741824 | | innodb_checksums | ON | | innodb_commit_concurrency | 0 | | innodb_concurrency_tickets | 500 | | innodb_data_file_path | ibdata1:10M:autoextend | | innodb_data_home_dir | | | innodb_adaptive_hash_index | ON | | innodb_doublewrite | ON | | innodb_fast_shutdown | 1 | | innodb_file_io_threads | 4 | | innodb_file_per_table | ON | | innodb_flush_log_at_trx_commit | 1 | | innodb_flush_method | | | innodb_force_recovery | 0 | | innodb_lock_wait_timeout | 50 | | innodb_locks_unsafe_for_binlog | OFF | | innodb_log_arch_dir | | | innodb_log_archive | OFF | | innodb_log_buffer_size | 8388608 | | innodb_log_file_size | 314572800 | | innodb_log_files_in_group | 2 | | innodb_log_group_home_dir | ./ | | innodb_max_dirty_pages_pct | 90 | | innodb_max_purge_lag | 0 | | innodb_mirrored_log_groups | 1 | | innodb_open_files | 300 | | innodb_rollback_on_timeout | OFF | | innodb_support_xa | ON | | innodb_sync_spin_loops | 20 | | innodb_table_locks | ON | | innodb_thread_concurrency | 8 | | innodb_thread_sleep_delay | 10000 | | interactive_timeout | 31536000 | | join_buffer_size | 2097152 | | key_buffer_size | 8384512 | | key_cache_age_threshold | 300 | | key_cache_block_size | 1024 | | key_cache_division_limit | 100 | | language | /usr/local/mysql-5.0.77-linux-i686-glibc23/share/mysql/english/ | | large_files_support | ON | | large_page_size | 0 | | large_pages | OFF | | lc_time_names | en_US | | license | GPL | | local_infile | ON | | locked_in_memory | OFF | | log | OFF | | log_bin | OFF | | log_bin_trust_function_creators | OFF | | log_error | | | log_queries_not_using_indexes | OFF | | log_slave_updates | OFF | | log_slow_queries | OFF | | log_warnings | 1 | | long_query_time | 10 | | low_priority_updates | OFF | | lower_case_file_system | OFF | | lower_case_table_names | 1 | | max_allowed_packet | 67108864 | | max_binlog_cache_size | 4294963200 | | max_binlog_size | 1073741824 | | max_connect_errors | 10 | | max_connections | 200 | | max_delayed_threads | 20 | | max_error_count | 64 | | max_heap_table_size | 33554432 | | max_insert_delayed_threads | 20 | | max_join_size | 18446744073709551615 | | max_length_for_sort_data | 1024 | | max_prepared_stmt_count | 16382 | | max_relay_log_size | 0 | | max_seeks_for_key | 4294967295 | | max_sort_length | 1024 | | max_sp_recursion_depth | 0 | | max_tmp_tables | 32 | | max_user_connections | 0 | | max_write_lock_count | 4294967295 | | multi_range_count | 256 | | myisam_data_pointer_size | 6 | | myisam_max_sort_file_size | 2146435072 | | myisam_recover_options | OFF | | myisam_repair_threads | 1 | | myisam_sort_buffer_size | 8388608 | | myisam_stats_method | nulls_unequal | | ndb_autoincrement_prefetch_sz | 1 | | ndb_force_send | ON | | ndb_use_exact_count | ON | | ndb_use_transactions | ON | | ndb_cache_check_time | 0 | | ndb_connectstring | | | net_buffer_length | 16384 | | net_read_timeout | 30 | | net_retry_count | 10 | | net_write_timeout | 60 | | new | OFF | | old_passwords | OFF | | open_files_limit | 8192 | | optimizer_prune_level | 1 | | optimizer_search_depth | 62 | | pid_file | /var/mysql/live/mysqld.pid | | plugin_dir | | | port | 3307 | | preload_buffer_size | 32768 | | profiling | OFF | | profiling_history_size | 15 | | protocol_version | 10 | | query_alloc_block_size | 8192 | | query_cache_limit | 1048576 | | query_cache_min_res_unit | 4096 | | query_cache_size | 0 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | | query_prealloc_size | 8192 | | range_alloc_block_size | 4096 | | read_buffer_size | 131072 | | read_only | OFF | | read_rnd_buffer_size | 262144 | | relay_log | | | relay_log_index | | | relay_log_info_file | relay-log.info | | relay_log_purge | ON | | relay_log_space_limit | 0 | | rpl_recovery_rank | 0 | | secure_auth | OFF | | secure_file_priv | | | server_id | 0 | | skip_external_locking | ON | | skip_networking | OFF | | skip_show_database | OFF | | slave_compressed_protocol | OFF | | slave_load_tmpdir | /tmp/ | | slave_net_timeout | 3600 | | slave_skip_errors | OFF | | slave_transaction_retries | 10 | | slow_launch_time | 2 | | socket | /tmp/mysql_live.sock | | sort_buffer_size | 2097152 | | sql_big_selects | ON | | sql_mode | | | sql_notes | ON | | sql_warnings | OFF | | ssl_ca | | | ssl_capath | | | ssl_cert | | | ssl_cipher | | | ssl_key | | | storage_engine | MyISAM | | sync_binlog | 0 | | sync_frm | ON | | system_time_zone | GMT | | table_cache | 2048 | | table_lock_wait_timeout | 50 | | table_type | MyISAM | | thread_cache_size | 0 | | thread_stack | 196608 | | time_format | %H:%i:%s | | time_zone | SYSTEM | | timed_mutexes | OFF | | tmp_table_size | 33554432 | | tmpdir | /tmp/ | | transaction_alloc_block_size | 8192 | | transaction_prealloc_size | 4096 | | tx_isolation | REPEATABLE-READ | | updatable_views_with_limit | YES | | version | 5.0.77 | | version_comment | MySQL Community Server (GPL) | | version_compile_machine | i686 | | version_compile_os | pc-linux-gnu | | wait_timeout | 31536000 | +---------------------------------+------------------------------------------------------------------+ 237 rows in set (0.00 sec)
这听起来很奇怪。 我不确定可以解决什么问题，但是不pipe你遇到什么问题，我都会推荐你做一些事情。
Mysql有相当数量的内部64位math。 所有的东西都是平等的，它总是在64位操作系统中运行得更快。 另外如果你要麻烦给你的服务器8GB的一个32位的Mysql仍然只能解决3GB的。 通过给操作系统更多的空间来caching文件等等，你仍然可以获得一些性能，但是Mysql本身不会受益太多。
特别是如果你正在使用disto Mysql为其构build软件包。 Mysql的最新版本是5.0.92。 虽然我不知道有任何修复，但最好保持更新。 Mysql的移动速度相当快，在主要版本的生命周期中速度和性能有很大的差异。
如果我在你的位置，我会启动一个新的8GB虚拟机，并安装Mysql 5.0.92。 不要忘记安装compat库，否则CentOS会认为你没有安装任何Mysql库。 我想从原始服务器转储并导入。 从旧到新设置复制，然后testing。 一旦它看起来很好的切换。