Shulou(Shulou.com)06/03 Report--

two。 IOPS description

2.1 IOPS (Input/OutputPer Second)

IOPS, that is, the amount of input and output per second (or the number of reads and writes), is one of the main indicators of disk performance.

IOPS refers to the number of Icano requests that can be processed by the system per unit time, usually in terms of the number of Icano requests per second, which are usually read or write data operation requests. Application of random read and write frequently

Such as OLTP (OnlineTransaction Processing), IOPS is the key indicator.

Another important indicator is data throughput (Throughput), which refers to the amount of data that can be successfully transferred per unit of time. For applications with a large number of sequential reads and writes, such as VOD (Video On Demand), more attention is paid to throughput metrics.

Traditional disk is essentially a mechanical device, such as FC, SAS, SATA disk, the speed is usually different from 5400/7200/10K/15K rpm. The key factor affecting the disk is the disk service time, that is, the time it takes for the disk to complete an I _ swap O request, which consists of seek time, rotation delay and data transmission time.

(1) seek time

Tseek is the time it takes to move the read-write head to the correct track. The shorter the seek time is, the faster the operation will be. Currently, the average seek time of the disk is generally in 3-15ms.

(2) rotation delay

Trotation is the time it takes for disk rotation to move the sector where the requested data is located below the read-write head. The rotation delay depends on the speed of the disk, which is usually represented by 1x2 of the time it takes for the disk to rotate for one week.

For example, a disk with an average rotation delay of 7200 rpm is about 60 million rpm, while a disk with a speed of 15000 rpm has an average rotation delay of about 2ms.

(3) data transmission time

Ttransfer refers to the time required to complete the transmission of the requested data, which depends on the data transfer rate, which is equal to the data size divided by the data transfer rate.

At present, IDE/ATA can reach 133MB/s (MBPS), SATA II can reach the interface data transfer rate of 300MB/s, and the data transmission time is usually much less than the first two parts of time.

IOPS (IO per second) = 1s/ (seek time + rotation delay + data transfer time)

Therefore, it is theoretically possible to calculate the maximum IOPS of the disk, that is, IOPS = 1000ms/ (Tseek + Troatation), ignoring the data transfer time. Assuming that the average physical seek time of the disk is 3ms and the disk speed is 7200, 10K and 15Krpm, the theoretical maximum values of disk IOPS are:

IOPS = 1000 / (3 + 6000Universe 7200Universe 2) = 140,

IOPS = 1000 / (3 + 60000 / 10000 lap 2) = 167,

IOPS = 1000 / (3 + 60000015000Universe 2) = 20000

2.2 IOPS of solid state disk

Solid state disk (SSD) is an electronic device, which avoids the time spent on seek and rotation of traditional disks, and the memory cell addressing cost is greatly reduced, so the IOPS can be very high, up to tens of thousands or even hundreds of thousands.

In the actual measurement, the IOPS value will be affected by many factors, including Icano load characteristics (read-write ratio, order and randomness, number of worker threads, queue depth, data record size), system configuration, operating system, disk drive and so on.

Therefore, when comparing and measuring disk IOPS, it must be carried out under the same test benchmark, even if there is a certain degree of random uncertainty.

In general, IOPS can be subdivided into the following metrics:

Toatal IOPS: disk IOPS in the case of mixed read / write and sequential random Icano load, which is most consistent with the actual Icano situation, and most applications pay attention to this indicator.

Random Read IOPS:100% randomly reads IOPS under load.

Random WriteIOPS:100% randomly writes IOPS under load.

Sequential ReadIOPS:100% IOPS in the case of sequential load reads.

Sequential WriteIOPS:100% writes IOPS under load sequentially.

III. ORION tool description

ORION (OracleI/O Calibration Tool) Oracle has launched a stand-alone tool for calibrating the performance of the database storage system Icano. For a description of the tool, refer to:

Oracle ORION IO testing tool

Http://blog.csdn.net/tianlesoftware/article/details/5965331

Let's test it with the ORION tool:

[root@qs-xe-dzora-pd software] # cat dave.lun

/ dev/sdb1

[root@qs-xe-dzora-pd software] #. / orion_linux_x86-64-run advanced-testname dave-num_disks 2

ORION: ORacle IO Numbers-- Version11.1.0.7.0

Dave_20111026_2026

Test will take approximately 16 minutes

Larger caches may take longer

View the generated results:

[root@qs-xe-dzora-pd software] # ls dave*

Dave_20111026_2026_iops.csv dave_20111026_2026_summary.txt dave.lun_20111026_2025_summary.txt

Dave_20111026_2026_lat.csv dave_20111026_2026_trace.txt

Dave_20111026_2026_mbps.csv dave.lun

[root@qs-xe-dzora-pd software] # cat dave_20111026_2026_summary.txt

ORION VERSION 11.1.0.7.0

Commandline:

-run advanced-testname dave-num_disks 2

This maps to this test:

Test: dave

Small IO size: 8 KB

Large IO size: 1024 KB

IO Types: Small RandomIOs, Large RandomIOs

Simulated Array Type: CONCAT

Write: 0%

Cache Size: Not Entered

Duration for each Data Point: 60 seconds

Small Columns:, 0

Large Columns:, 0, 1, 2, 3, 4

Total Data Points: 15

Name: / dev/sdb1 Size: 449495069184

1 FILEs found.

Maximum Large MBPS=159.61 @ Small=0 andLarge=4 #

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.