MySQL的QP

 
show global status where Variable_name in('com_select','com_insert','com_delete','com_update'); 
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磁盘IOPS计算与测量 

IOPS 是指单位时间内系统能处理的I/O请求数量，一般以每秒处理的I/O请求数量为单位，I/O请求通常为读或写数据操作请求。随机读写频繁的应用，如OLTP，IOPS是关键衡量指标。 
数据吞吐量(Throughput)，指单位时间内可以成功传输的数据数量。对于大量顺序读写的应用，如VOD(Video On Demand)，则更关注吞吐量指标。 
磁盘完成一个I/O请求所花费的时间，它由寻道时间、旋转延迟和数据传输时间三部分构成。 
寻道时间Tseek是指将读写磁头移动至正确的磁道上所需要的时间。寻道时间越短，I/O操作越快，目前磁盘的平均寻道时间一般在3－15ms。 
旋转延迟Trotation是指盘片旋转将请求数据所在扇区移至读写磁头下方所需要的时间。旋转延迟取决于磁盘转速，通常使用磁盘旋转一周所需时间的1/2表示。比如，7200 rpm的磁盘平均旋转延迟大约为60*1000/7200/2 = 4.17ms，而转速为15000 rpm的磁盘其平均旋转延迟约为2ms。 
数据传输时间Ttransfer是指完成传输所请求的数据所需要的时间，它取决于数据传输率，其值等于数据大小除以数据传输率。目前IDE/ATA能达到133MB/s，SATA II可达到300MB/s的接口数据传输率，数据传输时间通常远小于前两部分时间。 

因此，理论上可以计算出磁盘的平均最大IOPS，即IOPS = 1000 ms/ (Tseek + Troatation)，忽略数据传输时间。假设磁盘平均物理寻道时间为3ms, 磁盘转速为7200,10K,15K rpm，则磁盘IOPS理论最大值分别为， 
IOPS = 1000 / (3 + 60000/7200/2)  = 140 
IOPS = 1000 / (3 + 60000/10000/2) = 167 
IOPS = 1000 / (3 + 60000/15000/2) = 200 
固态硬盘SSD是一种电子装置， 避免了传统磁盘在寻道和旋转上的时间花费，存储单元寻址开销大大降低，因此IOPS可以非常高，能够达到数万甚至数十万。实际测量中，IOPS数值会受到很多因素的影响，包括I/O负载特征(读写比例，顺序和随机，工作线程数，队列深度，数据记录大小)、系统配置、操作系统、磁盘驱动等等。 
因此对比测量磁盘IOPS时，必须在同样的测试基准下进行，即便如何也会产生一定的随机不确定性。通常情况下，IOPS可细分为如下几个指标： 
Toatal IOPS，混合读写和顺序随机I/O负载情况下的磁盘IOPS，这个与实际I/O情况最为相符，大多数应用关注此指标。 
Random Read IOPS，100%随机读负载情况下的IOPS。 
Random Write IOPS，100%随机写负载情况下的IOPS。 
Sequential Read IOPS，100%顺序负载读情况下的IOPS。 
Sequential Write IOPS，100%顺序写负载情况下的IOPS。 

IOPS的测试benchmark工具主要有Iometer, IoZone, FIO等，可以综合用于测试磁盘在不同情形下的IOPS。对于应用系统，需要首先确定数据的负载特征，然后选择合理的IOPS指标进行测量和对比分析，据此选择合适的存储介质和软件系统

磁盘IOPS指标（参http://en.wikipedia.org/wiki/IOPS）

Some com­monly accepted aver­ages for random IO operations, calculated as 1/(seek + latency) = IOPS:

Device	Type	IOPS	Interface	Notes
7,200 rpm SATA drives	HDD	~75-100 IOPS[2]	SATA 3 Gbit/s
10,000 rpm SATA drives	HDD	~125-150 IOPS[2]	SATA 3 Gbit/s
10,000 rpm SAS drives	HDD	~140 IOPS[2]	SAS
15,000 rpm SAS drives	HDD	~175-210 IOPS[2]	SAS

Solid State Devices

Device	Type	IOPS	Interface	Notes
Simple SLC SSD	SSD	~400 IOPS[citation needed]	SATA 3 Gbit/s
Intel X25-M G2(MLC)	SSD	~8,600 IOPS[11]	SATA 3 Gbit/s	Intel's data sheet[12] claims 6,600/8,600 IOPS (80 GB/160 GB version) and 35,000 IOPS for random 4 KB writes and reads, respectively.
Intel X25-E(SLC)	SSD	~5,000 IOPS[13]	SATA 3 Gbit/s	Intel's data sheet[14] claims 3,300 IOPS and 35,000 IOPS for writes and reads, respectively. 5,000 IOPS are measured for a mix. Intel X25-E G1 has around 3 times higher IOPS compared to the Intel X25-M G2.[15]
G.Skill Phoenix Pro	SSD	~20,000 IOPS[16]	SATA 3 Gbit/s	SandForce-1200 based SSD drives with enhanced firmware, states up to 50,000 IOPS, but benchmarking shows for this particular drive ~25,000 IOPS for random read and ~15,000 IOPS for random write.[16]
OCZ Vertex 3	SSD	Up to 60,000 IOPS[17]	SATA 6 Gbit/s	Random Write 4 KB (Aligned)
Corsair Force Series GT	SSD	Up to 85,000 IOPS[18]	SATA 6 Gbit/s	240 GB Drive, 555 MB/s sequential read & 525 MB/s sequential write, Random Write 4 KB Test (Aligned)
OCZ Vertex 4	SSD	Up to 120,000 IOPS[19]	SATA 6 Gbit/s	256 GB Drive, 560 MB/s sequential read & 510 MB/s sequential write, Random Read 4 KB Test 90K IOPS, Random Write 4 KB Test 85K IOPS
Texas Memory Systems RamSan-20	SSD	120,000+ Random Read/Write IOPS[20]	PCIe	Includes RAM cache
Fusion-ioioDrive	SSD	140,000 Read IOPS, 135,000 Write IOPS[21]	PCIe
Virident SystemstachIOn	SSD	320,000 sustained READ IOPS using 4KB blocks and 200,000 sustained WRITE IOPS using 4KB blocks[22]	PCIe
OCZ RevoDrive 3 X2	SSD	200,000 Random Write 4K IOPS[23]	PCIe
Fusion-io ioDrive Duo	SSD	250,000+ IOPS[24]	PCIe
Violin MemoryViolin 3200	SSD	250,000+ Random Read/Write IOPS[25]	PCIe /FC/Infiniband/iSCSI	Flash Memory Array
WHIPTAIL, ACCELA	SSD	250,000/200,000+ Write/Read IOPS[26]	Fibre Channel, iSCSI, Infiniband/SRP, NFS, CIFS	Flash Based Storage Array
DDRdrive X1,	SSD	300,000+ (512B Random Read IOPS) and 200,000+ (512B Random Write IOPS)[27][28][29][30]	PCIe
SolidFireSF3010/SF6010	SSD	250,000 4KB Read/Write IOPS[31]	iSCSI	Flash Based Storage Array (5RU)
Texas Memory Systems RamSan-720 Appliance	SSD	500,000 Optimal Read, 250,000 Optimal Write 4KB IOPS[32]	FC / InfiniBand
OCZ Single SuperScale Z-Drive R4 PCI-Express SSD	SSD	Up to 500,000 IOPS[33]	PCIe
WHIPTAIL,INVICTA	SSD	650,000/550,000+ Read/Write IOPS[34]	Fibre Channel, iSCSI, Infiniband/SRP, NFS	Flash Based Storage Array
Violin MemoryViolin 6000	3RU Flash Memory Array	1,000,000+ Random Read/Write IOPS[35]	/FC/Infiniband/10Gb(iSCSI)/ PCIe
Texas Memory Systems RamSan-630 Appliance	SSD	1,000,000+ 4KB Random Read/Write IOPS[36]	FC / InfiniBand
Fusion-io ioDrive Octal (single PCI Express card)	SSD	1,180,000+ Random Read/Write IOPS[37]	PCIe
OCZ 2x SuperScale Z-Drive R4 PCI-Express SSD	SSD	Up to 1,200,000 IOPS[33]	PCIe
Texas Memory Systems RamSan-70	SSD	1,200,000 Random Read/Write IOPS[38]	PCIe	Includes RAM cache
Kaminario K2	Flash/DRAM/Hybrid SSD	Up to 1,200,000 IOPS SPC-1 IOPS with the K2-D (DRAM)[39][40]	FC
NetApp FAS6240 cluster	Flash/Disk	1,261,145 SPECsfs2008 nfsv3 IOPs using disks with virtual storage tiering.[41]	NFS, CIFS, FC, FCoE, iSCSI	SPECsfs2008 is the latest version of the Standard Performance Evaluation Corporation benchmark suite measuring file server throughput and response time, providing a standardized method for comparing performance across different vendor platforms. http://www.spec.org/sfs2008/
Fusion-io ioDrive2	SSD	Up to 9,608,000 IOPS[42]	PCIe