Introduction and Evaluation of sata sas ssd hard drive

SATA

The full name of Sata is serial Advanced Technology Attachment,Proposed by Intel, IBM, Dell, APT, maxtor, and SeagateHard Disk InterfaceSpecification.

The SATA hard drive adopts a new design structure, which features fast data transmission and space saving. It has many advantages over the IDE Hard Drive:

1. SATA hard disks are faster than IDE hard disks. Currently, Sata supports a peak transmission rate of 150 Mb/s. It will reach 300 MB/S and 600 Mb/s in the future. Then we will get a transmission rate of nearly 10 times faster than the IDE hard drive.

2. Compared with the pata40-pin data line of the IDE hard disk, the SATA cable is small and thin, and the transmission distance is far away. It can be extended to 1 m, making it easier to install the device and wiring in the device. The connector is small, which effectively improves the internal size of the computer.AirFlow also improves the heat dissipation in the chassis.

3. the power consumption of the IDE hard drive system is reduced. The SATA hard drive can work at a voltage of 500 mV.

4. SATA can be backward compatible with the PATA device by using a multi-purpose chipset or serial-parallel converter. Because SATA and PATA can use the same drive, you do not need to upgrade the operating system or perform other changes.

5. You do not need to set the jumper of the Master/Slave disk for Sata. The BIOS will number it in the order of 1, 2, and 3. This depends on the SATA connector to which the drive is connected (easy to install ). However, the IDE hard disk must be configured with a jumper to set the master/Slave disk. 

6. SATA also supports hot swapping and can be used like a USB flash drive. IDE Hard Disks do not support hot swapping.

 

SAS

SAS (Serial Attached SCSI) is a new generation of SCSI technology, which is the same as the popular Serial ATA (SATA) hard drive. It uses serial technology to achieve higher transmission speeds, and improve the internal space by shortening the connection line. SAS is a new interface developed after the parallel SCSI interface. This interface is designed to improve the efficiency, availability, and scalability of the storage system and provide compatibility with Sata hard disks. SAS interface technology is backward compatible with Sata.

In terms of interface standards, Sata is a sub-standard of SAS. Therefore, SAS controllers can directly control SATA hard disks, but SAS cannot be directly used in Sata environments, because the SATA controller cannot control the SAS Hard Disk

 

SSD

SSD is a technology that discards traditional magnetic media and uses electronic storage media for data storage and reading. It breaks through the performance bottleneck of traditional mechanical hard disks and has extremely high storage performance, it is regarded as a new star in the development of storage technology.

The solid state drive's fully integrated circuit-based, revolutionary design without any mechanical movement components, fundamentally solves the needs for data read/write stability in mobile office environments. The fully integrated circuit design can make solid state disks in any shape. Compared with traditional hard disks, SSD Solid State electronic disks have the following advantages:

First, SSD does not require a mechanical structure. It is completely semiconductor and there is no data search time, delay time, or disk seek time. The data access speed is fast, the Data Reading capability is more than 100 Mb/s, and the maximum is 300 MB/S. 

Second, SSD all uses flash memory chips, which are durable and shockproof. Even if a collision with hard objects occurs, the possibility of data loss can be minimized. 

Third, thanks to the absence of mechanical components and flash memory chips, SSD has no noise and low power consumption.

Fourth, light quality, 20-30 grams lighter than conventional 1.8 inch hard drives, making it possible for portable devices to carry multiple SSDS. At the same time, because of its complete semiconductors and no structural restrictions, special electronic hard disks with different interfaces and shapes can be designed according to the actual situation.

 

Performance Evaluation

Operating system Ubuntu 12.04

Test Tool FIO

Take sequential reading as an example. The command is as follows: FIO-name iops-RW = read-BS = 4 K-runtime = 60-iodepth 32-filename/dev/sda6-ioengine libaio-Direct = 1

RW = read indicates random reading, BS = 4 K indicates 4 K reading each time, and filename indicates the corresponding partition. Here I am/dev/sda6, direct = 1 indicates traversing the Linux Cache

We will test the sequential read, random read, sequential write, and random write speeds of SATA hard disks, SAS hard disks, and SSD hard disks in sequence.

 

Sequential read

Test command: FIO-name iops-RW = read-BS = 4 K-runtime = 60-iodepth 32-filename/dev/sda6-ioengine libaio-Direct = 1

 
Satajobs:1(F =1): [R] [16.4% done] [124.1 M/0 K/s] [31.3 K/0 iops] [ETA 00 m: 51 S]Sasjobs:1(F =1): [R] [16.4% done] [190 m/0 K/s] [41.3 K/0 iops] [ETA 00 m: 51 S]Ssdjobs:1(F =1): [R] [100.0%Done] [404 M/0 K/s] [103 K/0Iops] [ETA 00 m: 00 s]
 

We can see thatWhen a 4 KB data packet is continuously read:

The SSD speed can reach 404 Mb/s, And the iops can reach 103 K/s.

SAS provides a speed of 190 Mb/s and an iops of 41 K/s.

The SATA speed can reach 124 Mb/s, And the iops can reach 31 K/s.

For sequential read, SAS performs 1.3 times the SATA hard drive and 4 times the SATA hard drive.

 

Random read

Test command FIO-name iops-RW = randread-BS = 4 K-runtime = 60-iodepth 32-filename/dev/sda6-ioengine libaio-Direct = 1

Satajobs:1(F =1): [R] [41.0% done] [466 K/0 K/s] [114/0 iops] [ETA 00 m: 36 S]Sasjobs:1(F =1): [R] [41.0% done] [1784 K/0 K/s] [456/0 iops] [ETA 00 m: 36 S]Ssdjobs:1(F =1): [R] [100.0%Done] [505 m/0 K/s] [129 K/0Iops] [ETA 00 m: 00 s]
 

Random reading: SAS performs 4 times the SATA hard drive and SSD performs more than one thousand times the SATA hard drive.

 

Sequential write

Test command: FIO-name iops-RW = write-BS = 4 K-runtime = 60-iodepth 32-filename/dev/sda6-ioengine libaio-Direct = 1

Satajobs:  1 (F = 1 ): [W] [ 21.3 % Done ] [0 k/ 124.9 m /S] [ 0 / 31  . 3 K iops] [ETA 00 m: 48 s] sasjobs:  1 (F = 1 ): [W] [ 21.3 % Done ] [0 k/190 m/s] [ 0 / 36  . 3 K iops] [ETA 00 m: 48 s] ssdjobs:  1 (F = 1 ): [W] [ 100.0 % Done ] [0 k/592 m/s] [ 0 /152 K iops] [ETA 00 m: 00 s]

In the same 4 KB data packet write sequence, the SSD card scored 592 Mb/s, And the iops was 152 kb. The local hard disk is only 118 Mb/s, And the iops is only 30290.

 

Random write

Test command: FIO-name iops-RW = randwrite-BS = 4 K-runtime = 60-iodepth 32-filename/dev/sda6-ioengine libaio-Direct = 1

 Satajobs: 1 (F = 1 ):[ W ] [ 100.0 % Done ] [0 k/548 K/s] [ 0 / 134  Iops] [ETA 00 m: 00 s] sasjobs:  1 (F = 1 ):[ W ] [ 100.0 % Done ] [0 k/2000 K/s] [ 0 / 512  Iops] [ETA 00 m: 00 s] ssdjobs:  1 (F = 1 ): [W] [ 100.0 % Done ] [0 k/549 m/s] [ 0 /140 K iops] [ETA 00 m: 00 s]

In the next 4 kb packet random write operation, the SSD card once again demonstrated its superb Io performance, a random write rate of up to 549 Mb/s, and an iops of up to 140 KB. In contrast, the random read/write of the local hard disk is only 548kb/s, and the iops is 134.