Amazon EC2上的高iowait具有EBS卷的MySQL实例

我们有一台MySQL服务器运行在Amazon EC2 c1.medium实例上，依靠单个EBS卷使用ext3文件系统进行存储。

这个MySQL服务器被运行在一些Web服务器上的几个应用程序查询〜500 / ps，这些服务器也在Amazon EC2上。

正如你在下面看到的，服务器的负载平均和处理器闲置时间看起来不错，但是现在有一些令人担忧和担心的事情，这是它正在经历的高昂的爱荷华州。

另一个令我担忧的数字是iostat每秒传输速度（tps）的数量，大部分时间都在450以上。 在对这个话题进行了一些研究之后，我看到一些人说这是一个EBS量太多的问题： https : //forums.aws.amazon.com/thread.jspa? threadID =30769

• MogileFS / GlusterFS / etc + Amazon EBS + Amazon EC2
• 如何使Cent OS安装类似于基于EC2 rhel的实例？
• 如何从头创build基于EBS的EC2 AMI？
• 从现有的EBS卷引导EC2实例
• 运行Ubuntu的EBS支持的EC2实例的自动快照

顺便说一下，下面看到的命令输出在高峰时间没有被捕获。 这就是服务器行为/执行大部分时间的方式。

那么，所有人都说，这里去我的问题：

1-是时候考虑移动RAID架构（我会说RAID 0）？

我应该花时间在一个集群解决scheme，如MySQL集群吗？

3-你认为这种情况严重影响我们的应用程序吗？ 如果我们迁移到RAID 0和/或集群解决scheme，它们的性能会好吗？ （看起来应用程序到目前为止是快乐的，但他们会更快乐吗？）

请让我知道，如果你需要任何进一步的信息。

~ # uptime 12:34:14 up 2 days, 4:06, 1 user, load average: 2.24, 1.90, **1.84** ######################################################## ~ # vmstat 5 procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ rb swpd free buff cache si so bi bo in cs us sy id **wa** st 0 1 52 11168 16420 1498728 0 0 4586 231 11 81 6 3 52 39 0 2 1 52 10460 16320 1499588 0 0 11631 397 3194 4319 10 4 47 39 0 4 1 52 11448 16064 1499156 0 0 12231 592 2301 3331 9 5 50 36 0 4 0 52 10328 16068 1500176 0 0 8578 392 2131 2745 8 6 49 37 0 0 1 52 11164 15732 1499928 0 0 9604 578 2609 3510 7 4 49 40 0 0 1 52 10824 15768 1499836 0 0 5038 634 1912 2509 8 3 47 42 0 3 1 52 12040 15888 1498096 0 0 5068 204 1927 2531 10 8 45 37 0 8 2 52 11252 15784 1499272 0 0 8521 390 2437 3100 14 15 39 31 0 1 2 52 11436 15724 1499748 0 0 8287 401 2159 3113 11 10 42 36 1 0 1 52 12016 15704 1498752 0 0 11576 499 3324 3984 16 17 31 36 0 1 1 52 10536 15664 1500508 0 0 8430 718 2686 3265 15 14 37 34 0 1 1 52 10300 15676 1500744 0 0 10186 720 2488 3488 16 5 45 34 0 ######################################################## ~ # iostat -dm 5 /dev/sdf Linux 2.6.21.7-2.fc8xen (database-new) 01/20/12 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 464.81 8.84 0.33 1658860 61390 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 402.20 7.39 0.43 36 2 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 431.40 7.74 0.32 38 1 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 461.40 8.26 0.39 41 1 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 475.65 9.20 0.29 46 1 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 534.80 9.82 0.52 49 2 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sdf 526.60 9.97 0.52 49 2 ######################################################## ~ # iostat -mdx 5 /dev/sdf Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 22.21 46.28 427.47 37.54 8.84 0.33 40.38 1.78 3.82 1.72 79.87 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 22.36 80.04 450.30 60.48 9.29 0.55 39.44 1.45 2.85 1.58 80.48 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 23.40 43.60 370.60 47.00 7.75 0.35 39.76 1.45 3.47 1.97 82.08 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 20.20 33.20 382.60 29.60 8.02 0.25 41.05 1.31 3.17 2.11 87.12 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 28.80 35.20 422.40 33.40 9.04 0.27 41.80 1.45 3.19 1.95 88.96 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 14.20 45.00 291.80 51.40 5.97 0.38 37.86 1.45 4.22 2.50 85.68 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 19.16 56.89 535.33 41.32 11.44 0.38 42.00 1.49 2.59 1.53 88.46 Device: rrqm/s wrqm/sr/sw/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sdf 20.40 81.40 233.00 64.40 4.86 0.57 37.39 1.74 5.84 3.18 94.72 

################################################## my.cnf中

 [mysqld] datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock user=mysql long_query_time=1 key_buffer = 64M thread_cache_size = 30 table_cache = 1024 table_definition_cache = 512 query_cache_type = 1 query_cache_size = 64M tmp_table_size = 64M max_heap_table_size = 64M innodb_buffer_pool_size = 512M old_passwords=1 max_connections=400 wait_timeout=30 [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid [ndbd] connect-string="nodeid=2;host=localhost:1186" [ndb_mgm] connect-string="host=localhost:1186" 

##################################################杂项的调整脚本输出

 ~ # ./tuning-primer.sh -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.1.52 i686 Uptime = 0 days 1 hrs 1 min 1 sec Avg. qps = 517 Total Questions = 1894942 Threads Connected = 94 Warning: Server has not been running for at least 48hrs. It may not be safe to use these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is NOT enabled. Current long_query_time = 1.000000 sec. You have 207 out of 1894981 that take longer than 1.000000 sec. to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is NOT enabled. You will not be able to do point in time recovery See http://dev.mysql.com/doc/refman/5.1/en/point-in-time-recovery.html WORKER THREADS Current thread_cache_size = 30 Current threads_cached = 8 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 400 Current threads_connected = 93 Historic max_used_connections = 195 The number of used connections is 48% of the configured maximum. Your max_connections variable seems to be fine. INNODB STATUS Current InnoDB index space = 1.33 G Current InnoDB data space = 5.04 G Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 512 M Depending on how much space your innodb indexes take up it may be safe to increase this value to up to 2 / 3 of total system memory MEMORY USAGE Max Memory Ever Allocated : 1.13 G Configured Max Per-thread Buffers : 1.04 G Configured Max Global Buffers : 642 M Configured Max Memory Limit : 1.67 G Physical Memory : 1.70 G Max memory limit exceeds 90% of physical memory KEY BUFFER Current MyISAM index space = 379 M Current key_buffer_size = 64 M Key cache miss rate is 1 : 162 Key buffer free ratio = 80 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 64 M Current query_cache_used = 43 M Current query_cache_limit = 1 M Current Query cache Memory fill ratio = 67.44 % Current query_cache_min_res_unit = 4 K MySQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 2 M Current read_rnd_buffer_size = 256 K Sort buffer seems to be fine JOINS Current join_buffer_size = 132.00 K You have had 4013 queries where a join could not use an index properly You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log. If you are unable to optimize your queries you may want to increase your join_buffer_size to accommodate larger joins in one pass. Note! This script will still suggest raising the join_buffer_size when ANY joins not using indexes are found. OPEN FILES LIMIT Current open_files_limit = 2458 files The open_files_limit should typically be set to at least 2x-3x that of table_cache if you have heavy MyISAM usage. Your open_files_limit value seems to be fine TABLE CACHE Current table_open_cache = 1024 tables Current table_definition_cache = 512 tables You have a total of 45237 tables You have 1024 open tables. Current table_cache hit rate is 0% , while 100% of your table cache is in use You should probably increase your table_cache You should probably increase your table_definition_cache value. TEMP TABLES Current max_heap_table_size = 64 M Current tmp_table_size = 64 M Of 38723 temp tables, 44% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 128 K Current table scan ratio = 537 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 1 : 954 You may benefit from selective use of InnoDB. If you have long running SELECT's against MyISAM tables and perform frequent updates consider setting 'low_priority_updates=1' If you have a high concurrency of inserts on Dynamic row-length tables consider setting 'concurrent_insert=2'.