关注点
1. CPU ：%user，%sys，%idle，%iowait2. 内存：avalabel ，cache。swap，以及内存泄漏和OOM3. I/O :iops ,吞吐，时延，利用率4. 网络 ：吞吐 (特别关注小包收发频率)复制
CPU
top
top - 09:28:09 up 79 days, 15:24, 2 users, load average: 0.02, 0.08, 0.04Tasks: 123 total, 1 running, 122 sleeping, 0 stopped, 0 zombie%Cpu(s): 2.1 us, 0.5 sy, 0.0 ni, 97.4 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 stKiB Mem : 4046300 total, 2422244 free, 91868 used, 1532188 buff/cacheKiB Swap: 4194300 total, 4156212 free, 38088 used. 3661064 avail MemPID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND761 root 20 0 80264 1428 1264 S 0.3 0.0 76:46.85 gapd1 root 20 0 38208 5392 3368 S 0.0 0.1 7:31.33 systemd2 root 20 0 0 0 0 S 0.0 0.0 0:00.05 kthreadd3 root 20 0 0 0 0 S 0.0 0.0 5:49.22 ksoftirqd/05 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H7 root 20 0 0 0 0 S 0.0 0.0 14:40.66 rcu_sched8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh9 root rt 0 0 0 0 S 0.0 0.0 3:10.08 migration/010 root rt 0 0 0 0 S 0.0 0.0 0:23.44 watchdog/011 root rt 0 0 0 0 S 0.0 0.0 0:17.68 watchdog/112 root rt 0 0 0 0 S 0.0 0.0 3:09.57 migration/113 root 20 0 0 0 0 S 0.0 0.0 5:50.96 ksoftirqd/115 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/1:0H16 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kdevtmpfs17 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 netns18 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 perf19 root 20 0 0 0 0 S 0.0 0.0 0:02.70 khungtaskd20 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 writeback21 root 25 5 0 0 0 S 0.0 0.0 0:00.00 ksmd23 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 crypto24 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kintegrityd25 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 bioset26 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kblockd27 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 ata_sff28 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 md29 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 devfreq_wq33 root 20 0 0 0 0 S 0.0 0.0 0:30.66 kswapd034 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 vmstat35 root 20 0 0 0 0 S 0.0 0.0 0:00.01 fsnotify_mark复制
主要关注项1. load average, 5 分钟 10 分钟 ，15 分钟的负载变化2. cpu 的使用率 查看整体占比是多少 （也可以 top 进入界面 1，查看每个cpu的使用情况）如果:%user 占比高，可能是无索引，group by ，order by 无索引，慢sql 多如果：%sys 占比高,可能是numa未关闭,也可能是连接数过多如果 是 wa% 占比高的话，可能是io 成为瓶颈 ，需要具体判断 io 慢在哪里一般 id% 剩余 大于90 ，是正常的复制
内存
ubuntu@i-p8v1yk5a:~$ free -htotal used free shared buff/cache availableMem: 3.9G 88M 2.3G 4.5M 1.5G 3.5GSwap: 4.0G复制
1. 当 total - (free + buffer+cache) > 1/3 total 时 可能发生的内存泄漏 ， 有大于 1/3 total，没有回收2. 当内存不够用的情况,会发生 OOM （out of memory）,记录在 grep -i out /var/log/messages* 会记录oom 是否发生 如果发生了 ，需要具体分析是否数据库参数的值是否合理3. 从中可以查看 swap 的使用率,一般数据库不建议使用swap,出现swap的情况 ，可能是 NUMA 未关闭，也可能是在服务器使用的时期某一段时间内存不够，使用到了swap会导致数据库响应时间变长grep swap etc/sysctl.confvm.swappiness=1这是一个优先级,使用swap 的可能性，值越大使用的可能性越高 time). b: The number of processes in uninterruptible sleep. Memory swpd: the amount of virtual memory used. free: the amount of idle memory. buff: the amount of memory used as buffers. cache: the amount of memory used as cache. inact: the amount of inactive memory. (-a option) active: the amount of active memory. (-a option) Swap si: Amount of memory swapped in from disk (/s). so: Amount of memory swapped to disk (/s). IO bi: Blocks received from a block device (blocks/s). bo: Blocks sent to a block device (blocks/s). System in: The number of interrupts per second, including the clock. cs: The number of context switches per second. CPU These are percentages of total CPU time. us: Time spent running non-kernel code. (user time, including nice time) sy: Time spent running kernel code. (system time) id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time. wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle. st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.复制
IO
ubuntu@i-p8v1yk5a:~$ iostat -m -x 1 5Linux 4.4.0-116-generic (i-p8v1yk5a) 05/31/2021 _x86_64_ (2 CPU)avg-cpu: %user %nice %system %iowait %steal %idle1.68 0.00 0.78 0.04 0.01 97.49Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %utilvda 0.00 0.26 0.01 0.26 0.00 0.00 28.52 0.00 15.27 1.78 16.02 0.23 0.01vdb 0.00 0.03 0.00 0.00 0.00 0.00 66.97 0.00 0.72 0.14 0.93 0.55 0.00vdc 0.00 0.58 0.05 0.87 0.01 0.04 111.18 0.05 57.42 7.85 60.00 0.93 0.09avg-cpu: %user %nice %system %iowait %steal %idle1.51 0.00 2.01 0.00 0.00 96.48Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %utilvda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00vdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00vdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00avg-cpu: %user %nice %system %iowait %steal %idle3.48 0.00 1.00 0.00 0.00 95.52Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %utilvda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00vdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00vdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00avg-cpu: %user %nice %system %iowait %steal %idle0.00 0.00 0.00 0.00 0.00 100.00Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %utilvda 0.00 0.00 0.00 3.00 0.00 0.01 8.00 0.00 0.00 0.00 0.00 0.00 0.00vdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00vdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
详情 man iostatThe iostat command generates two types of reports, the CPU Utilization report and the Device Utilization report.CPU Utilization ReportThe first report generated by the iostat command is the CPU Utilization Report. For multiprocessor systems, the CPU values are global averages among all processors. The report has the following format:%userShow the percentage of CPU utilization that occurred while executing at the user level (application).%niceShow the percentage of CPU utilization that occurred while executing at the user level with nice priority.%systemShow the percentage of CPU utilization that occurred while executing at the system level (kernel).%iowaitShow the percentage of time that the CPU or CPUs were idle during which the system had an outstanding disk I/O request.%stealShow the percentage of time spent in involuntary wait by the virtual CPU or CPUs while the hypervisor was servicing another virtual processor.%idleShow the percentage of time that the CPU or CPUs were idle and the system did not have an outstanding disk I/O request.Indicate the amount of data written to the device expressed in a number of blocks (kilobytes, megabytes) per second.Blk_read (kB_read, MB_read)The total number of blocks (kilobytes, megabytes) read.Blk_wrtn (kB_wrtn, MB_wrtn)The total number of blocks (kilobytes, megabytes) written.rrqm/sThe number of read requests merged per second that were queued to the device.wrqm/sThe number of write requests merged per second that were queued to the device.r/sThe number (after merges) of read requests completed per second for the device.w/sThe number (after merges) of write requests completed per second for the device.rsec/s (rkB/s, rMB/s)The number of sectors (kilobytes, megabytes) read from the device per second.wsec/s (wkB/s, wMB/s)The number of sectors (kilobytes, megabytes) written to the device per second.avgrq-szThe average size (in sectors) of the requests that were issued to the device.avgqu-szThe average queue length of the requests that were issued to the device.awaitThe average time (in milliseconds) for I/O requests issued to the device to be served. This includes the time spent by the requests in queue and the time spent servicing them.r_awaitThe average time (in milliseconds) for read requests issued to the device to be served. This includes the time spent by the requests in queue and the time spent servicing them.w_awaitThe average time (in milliseconds) for write requests issued to the device to be served. This includes the time spent by the requests in queue and the time spent servicing them.svctmThe average service time (in milliseconds) for I/O requests that were issued to the device. Warning! Do not trust this field any more. This field will be removed in a future sysstat version.%utilPercentage of elapsed time during which I/O requests were issued to the device (bandwidth utilization for the device). Device saturation occurs when this value is close to 100%.关注点iops = r/s + w/s磁盘 吞吐 =r/MBs + w/MBsawait 响应时间 单位是 毫秒%util io 设备的繁忙程度 ，超过 50% 就需要关注，可能是平均值中隐藏的峰值也可以 结合 iotop 输出的 TID 和 MySQL threads.THREAD_OS_ID 的字段复制
网络
[root@zgs ~]# sar -n DEV 1Linux 3.10.0-957.el7.x86_64 (zgs) 11/29/2020 _x86_64_ (1 CPU)02:41:53 PM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s rxmcst/s02:41:54 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:54 PM virbr0-nic 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:54 PM virbr0 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:54 PM ens33 3.00 1.00 0.26 0.17 0.00 0.00 0.0002:41:54 PM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s rxmcst/s02:41:55 PM lo 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:55 PM virbr0-nic 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:55 PM virbr0 0.00 0.00 0.00 0.00 0.00 0.00 0.0002:41:55 PM ens33 3.03 3.03 0.22 0.74 0.000.00 0.00复制
关注点rxpck/s 每秒接收的数据包总数。txpck /秒 每秒传输的数据包总数。rxkB /秒 每秒接收的千字节总数。txkB /秒每秒传输的千字节总数。rxcmp /秒 每秒接收的压缩数据包数（用于cslip等）。txcmp /秒 每秒传输的压缩数据包数。rxmcst /秒 每秒接收到的组播数据包数。主要观察每秒的网络吞吐 即 rxKB + txKB 的大小一般网卡1/10左右网卡就满了检查TCP 的连接使用情况 active/s ,passive/s retrans/ssar -n TCP,ETCP 1复制
系统整体
ubuntu@i-p8v1yk5a:~$ vmstat 1 10procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----r b swpd free buff cache si so bi bo in cs us sy id wa st2 0 38088 2423024 334008 1198220 0 0 5 23 2 3 2 1 97 0 00 0 38088 2423072 334008 1198220 0 0 0 0 79 91 0 0 100 0 00 0 38088 2422900 334008 1198220 0 0 0 0 107 182 1 0 100 0 00 0 38088 2422692 334008 1198220 0 0 0 0 148 261 2 1 97 0 00 0 38088 2422856 334008 1198212 0 0 0 0 58 76 0 0 100 0 00 0 38088 2422664 334008 1198212 0 0 0 0 62 82 0 0 100 0 00 0 38088 2422756 334008 1198212 0 0 0 0 89 140 0 1 99 0 00 0 38088 2422468 334008 1198212 0 0 0 0 134 311 4 2 93 0 00 0 38088 2422604 334008 1198240 0 0 0 0 72 106 0 0 100 0 00 0 38088 2422604 334008 1198240 0 0 0 12 74 95 0 0 100 0 0
详情可以 man vmstatFIELD DESCRIPTION FOR VM MODEProcsr: The number of runnable processes (running or waiting for run time).b: The number of processes in uninterruptible sleep.Memoryswpd: the amount of virtual memory used.free: the amount of idle memory.buff: the amount of memory used as buffers.cache: the amount of memory used as cache.inact: the amount of inactive memory. (-a option)active: the amount of active memory. (-a option)Swapsi: Amount of memory swapped in from disk (/s).so: Amount of memory swapped to disk (/s).IObi: Blocks received from a block device (blocks/s).bo: Blocks sent to a block device (blocks/s).Systemin: The number of interrupts per second, including the clock.cs: The number of context switches per second.CPUThese are percentages of total CPU time.us: Time spent running non-kernel code. (user time, including nice time)sy: Time spent running kernel code. (system time)id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle.st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.关注点:可以了解系统cpu、内存、io、swap使用情况以及运行的进程的数量复制
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