Solid State Drives SAS vs. SATA. What to choose?
Good afternoon, habra people!
HGST's blog after some break with you again. And today we would like to talk about the advantages of SAS solid-state drives over SATA drives.
The SAS interface, which supports communications between devices, is designed for use at the corporate level and provides scalability, reliability and high availability of data, while SATA devices are optimized for cheaper user applications.
Because disk manufacturers use the SAS interface for high-performance drives, and SATA for client drives and high-capacity storage devices, manufacturers of solid-state drives (SSD) generally continue to use the same separation. Currently, enterprise-class SSDs with SATA interface are also on the market, providing high performance. However, using the SAS interface with more error-resistant flash devices, controllers, and firmware, we get an excellent solution for enterprise-level workloads, such as online transaction processing (OLTP), high performance computing (HPC), data, data warehousing / data logging, virtualization and virtual PC infrastructure, working with large amounts of data and hyper-scaled data, messaging and collaboration, interface Web servers, the transmission of multimedia streams and providing video on demand (VOD), cloud computing and data storage device Tier-0 for NAS and SAN networks.
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With the characteristics of the SAS interface and the industry-leading technologies of HGST, such as CellCare, PowerSafe and Data Path Protection, you get the following benefits:
• Stable, high-performance SSD operation over the entire life cycle
• Durability
• Scalability
• Reliability in operation
• High data availability
• Device data manageability
• Interaction with modernized system architecture
The workloads that must support enterprise-class solid-state SAS drives include:
• Online Transaction Processing (OLTP)
• High Performance Computing (HPC)
• Accelerating the database
• Organization of data storage and storage of user data
• Virtualization and virtual PC infrastructure
• Analysis of large amounts of data and hyper-scalable data
• Messaging and collaboration software
• Interface with web servers
• Streaming Media and Video On Demand (VOD)
• Cloud computing
• Tier-0 storage devices for SAN and NAS systems
SAS (serial SCSI) and SATA (serial ATA) are standard protocols for transferring data between connected devices. They are designed to enable computers to communicate with peripheral devices, such as external memory controllers and hard drives. Both interfaces (SAS and SATA) have a long history of development: they first appeared in the 1980s as parallel interfaces, and about 10 years ago were converted to serial protocols in order to further improve performance. When used with an external memory controller, the SAS or SATA interface can be used as an external interface of servers, as well as an internal interface for connecting hard drives and SSDs. The controller can support many types of interfaces, but the drives have only one type of interface - SAS or SATA. The interface is independent of the storage device (for example, flash memory, hard disk) or the quality of components or firmware within the disk. From this point of view, SAS and SATA interfaces behave the same.
Let us now consider the main parameters of drives.
Performance
• SCSI protocol. The SCSI protocol used by the SAS interface is faster and performs multiple, simultaneous data I / O operations more efficiently than the ATA parallel interface command set (SATA).
• Increase data transfer rate from 6 Gb / s to 12 Gb / s and then to 24 Gb / s. The SAS interface allows you to increase the data transfer rate from 6 Gb / s to 12 Gb / s; in addition, there is a clear roadmap to further increase the speed to 24 Gb / s. Currently, the SATA interface supports data transfer rates of up to 6 Gb / s, while there are no specific plans to increase speed in the future.
• Queues of marked commands. Most SAS drives support a queue of commands with a depth of 128 (the limit of the protocol is 65,536), which makes it possible to reduce latency and improve performance with high workloads. Hardware installation of the SATA command order supports only 32 commands.
• Dual ports and multi-channel I / O. SAS interface disks are equipped with dual ports and support multiple initiators in the storage system; thus, multi-channel I / O and load balancing increase performance. SATA does not support multiple initiators, and most SATA drives do not have dual ports.
• Full duplex data transfer. SAS drives support full duplex mode (simultaneous data transfer in two directions), while SATA drives work in half duplex mode (data transfer in one direction).
Scalability
• Multiple drives can be connected to one port. The SAS interface supports a port expander for up to 255 devices (a two-tier structure), so up to 65,635 disks can be connected to a single initiator port. SATA uses only point-to-point connections.
• Use of extended cables. Using SAS devices will provide a more convenient process for expanding the data center (data center), since they allow the use of passive copper cables up to 10 m long and optical cables up to 100 m long. SATA does not allow the use of cables longer than 2 meters.
• Scalable performance. The performance of solid state SAS drives in a RAID configuration is more scalable than SATA drives.
• Compatible with SATA interface. External memory controllers with a SAS interface support SATA disks, which provide long-distance data storage using both SAS and SATA drives in a single array. However, in turn, SATA does not support SAS drives.
High data availability
• Dual ports for fault tolerance. SAS supports dual ports, while most SATA drives do not have them.
• Several initiators. The SAS interface allows you to connect multiple controllers to a set of hard drives in the storage system, which ensures their quick replacement and failover. SATA interface does not have such capabilities.
• Connection in the "hot" mode. SAS and SATA drives can be hot-swappable.
Interaction with modernized system architecture
• Roadmap for enhanced functionality in the future. In the plans of manufacturers of devices with SAS interface - an increase in the data transfer rate up to 24 Gb / s and, probably, even higher, while for SATA there is no such roadmap and the data transfer rate is limited by the current value of 6 Gb / s. Through the use of SAS, enterprises can upgrade their fleet of devices and move to faster drives in the future, while maintaining compatibility with previous versions used in the existing infrastructure.
• SCSI. Since most drives installed in an enterprise use a set of SCSI commands, the SAS interface retains compatibility with various generations of storage systems.
HGST SSDs are characterized by high performance over the life of the drive. They use innovative technologies Advanced Flash Management and CellCare, which provide extremely high speed in sequential and random read / write mode. Solid-state drives work much faster than hard drives, although over time the flash memory cells wear out and their speed decreases, especially with an increase in the number of programs installed / deleted files from the disk. HGST's Advanced Flash Management technology uses a traditional algorithm for wear leveling, as well as schemes for detecting and correcting errors, repairing damaged blocks and eliminating data redundancy to increase the service life, reliability and performance of SSDs.
HGST CellCare is a proprietary technology for the production of flash memory controllers to ensure the durability, performance and reliability of enterprise-class devices using cost-effective, high-density logic chip elements for devices with flash memory. CellCare technology is based on dynamically tracking cell parameters as they wear out and using prediction technologies to minimize the wear and tear of NAND flash memory chips by creating adaptive feedback between flash memory and the controller. An equally important aspect of Cellcare technology is the ability to control the effect of aging flash memory and to prevent a decrease in the speed of SSD-drives as their service life increases. This feature of the unique Cellcare technology ensures trouble-free operation and high performance over the entire service life of the HGST SSD.
Now, when the cost of storing data has increased significantly due to changes in exchange rates, the choice of components of the IT infrastructure has to be resourceful and compromise. In our opinion, repeatedly proven reliability and high performance throughout the entire service life should definitely be taken into account along with other factors. Indeed, in the medium and long term, such a decision will pay for itself in full.
In the next post, we will continue the conversation about SSD drives and consider other advantages of HGST in this area.
HGST's blog after some break with you again. And today we would like to talk about the advantages of SAS solid-state drives over SATA drives.
The SAS interface, which supports communications between devices, is designed for use at the corporate level and provides scalability, reliability and high availability of data, while SATA devices are optimized for cheaper user applications.
Because disk manufacturers use the SAS interface for high-performance drives, and SATA for client drives and high-capacity storage devices, manufacturers of solid-state drives (SSD) generally continue to use the same separation. Currently, enterprise-class SSDs with SATA interface are also on the market, providing high performance. However, using the SAS interface with more error-resistant flash devices, controllers, and firmware, we get an excellent solution for enterprise-level workloads, such as online transaction processing (OLTP), high performance computing (HPC), data, data warehousing / data logging, virtualization and virtual PC infrastructure, working with large amounts of data and hyper-scaled data, messaging and collaboration, interface Web servers, the transmission of multimedia streams and providing video on demand (VOD), cloud computing and data storage device Tier-0 for NAS and SAN networks.
')
With the characteristics of the SAS interface and the industry-leading technologies of HGST, such as CellCare, PowerSafe and Data Path Protection, you get the following benefits:
• Stable, high-performance SSD operation over the entire life cycle
• Durability
• Scalability
• Reliability in operation
• High data availability
• Device data manageability
• Interaction with modernized system architecture
The workloads that must support enterprise-class solid-state SAS drives include:
• Online Transaction Processing (OLTP)
• High Performance Computing (HPC)
• Accelerating the database
• Organization of data storage and storage of user data
• Virtualization and virtual PC infrastructure
• Analysis of large amounts of data and hyper-scalable data
• Messaging and collaboration software
• Interface with web servers
• Streaming Media and Video On Demand (VOD)
• Cloud computing
• Tier-0 storage devices for SAN and NAS systems
SAS (serial SCSI) and SATA (serial ATA) are standard protocols for transferring data between connected devices. They are designed to enable computers to communicate with peripheral devices, such as external memory controllers and hard drives. Both interfaces (SAS and SATA) have a long history of development: they first appeared in the 1980s as parallel interfaces, and about 10 years ago were converted to serial protocols in order to further improve performance. When used with an external memory controller, the SAS or SATA interface can be used as an external interface of servers, as well as an internal interface for connecting hard drives and SSDs. The controller can support many types of interfaces, but the drives have only one type of interface - SAS or SATA. The interface is independent of the storage device (for example, flash memory, hard disk) or the quality of components or firmware within the disk. From this point of view, SAS and SATA interfaces behave the same.
Let us now consider the main parameters of drives.
Performance
• SCSI protocol. The SCSI protocol used by the SAS interface is faster and performs multiple, simultaneous data I / O operations more efficiently than the ATA parallel interface command set (SATA).
• Increase data transfer rate from 6 Gb / s to 12 Gb / s and then to 24 Gb / s. The SAS interface allows you to increase the data transfer rate from 6 Gb / s to 12 Gb / s; in addition, there is a clear roadmap to further increase the speed to 24 Gb / s. Currently, the SATA interface supports data transfer rates of up to 6 Gb / s, while there are no specific plans to increase speed in the future.
• Queues of marked commands. Most SAS drives support a queue of commands with a depth of 128 (the limit of the protocol is 65,536), which makes it possible to reduce latency and improve performance with high workloads. Hardware installation of the SATA command order supports only 32 commands.
• Dual ports and multi-channel I / O. SAS interface disks are equipped with dual ports and support multiple initiators in the storage system; thus, multi-channel I / O and load balancing increase performance. SATA does not support multiple initiators, and most SATA drives do not have dual ports.
• Full duplex data transfer. SAS drives support full duplex mode (simultaneous data transfer in two directions), while SATA drives work in half duplex mode (data transfer in one direction).
Scalability
• Multiple drives can be connected to one port. The SAS interface supports a port expander for up to 255 devices (a two-tier structure), so up to 65,635 disks can be connected to a single initiator port. SATA uses only point-to-point connections.
• Use of extended cables. Using SAS devices will provide a more convenient process for expanding the data center (data center), since they allow the use of passive copper cables up to 10 m long and optical cables up to 100 m long. SATA does not allow the use of cables longer than 2 meters.
• Scalable performance. The performance of solid state SAS drives in a RAID configuration is more scalable than SATA drives.
• Compatible with SATA interface. External memory controllers with a SAS interface support SATA disks, which provide long-distance data storage using both SAS and SATA drives in a single array. However, in turn, SATA does not support SAS drives.
High data availability
• Dual ports for fault tolerance. SAS supports dual ports, while most SATA drives do not have them.
• Several initiators. The SAS interface allows you to connect multiple controllers to a set of hard drives in the storage system, which ensures their quick replacement and failover. SATA interface does not have such capabilities.
• Connection in the "hot" mode. SAS and SATA drives can be hot-swappable.
Interaction with modernized system architecture
• Roadmap for enhanced functionality in the future. In the plans of manufacturers of devices with SAS interface - an increase in the data transfer rate up to 24 Gb / s and, probably, even higher, while for SATA there is no such roadmap and the data transfer rate is limited by the current value of 6 Gb / s. Through the use of SAS, enterprises can upgrade their fleet of devices and move to faster drives in the future, while maintaining compatibility with previous versions used in the existing infrastructure.
• SCSI. Since most drives installed in an enterprise use a set of SCSI commands, the SAS interface retains compatibility with various generations of storage systems.
HGST SSDs are characterized by high performance over the life of the drive. They use innovative technologies Advanced Flash Management and CellCare, which provide extremely high speed in sequential and random read / write mode. Solid-state drives work much faster than hard drives, although over time the flash memory cells wear out and their speed decreases, especially with an increase in the number of programs installed / deleted files from the disk. HGST's Advanced Flash Management technology uses a traditional algorithm for wear leveling, as well as schemes for detecting and correcting errors, repairing damaged blocks and eliminating data redundancy to increase the service life, reliability and performance of SSDs.
HGST CellCare is a proprietary technology for the production of flash memory controllers to ensure the durability, performance and reliability of enterprise-class devices using cost-effective, high-density logic chip elements for devices with flash memory. CellCare technology is based on dynamically tracking cell parameters as they wear out and using prediction technologies to minimize the wear and tear of NAND flash memory chips by creating adaptive feedback between flash memory and the controller. An equally important aspect of Cellcare technology is the ability to control the effect of aging flash memory and to prevent a decrease in the speed of SSD-drives as their service life increases. This feature of the unique Cellcare technology ensures trouble-free operation and high performance over the entire service life of the HGST SSD.
Now, when the cost of storing data has increased significantly due to changes in exchange rates, the choice of components of the IT infrastructure has to be resourceful and compromise. In our opinion, repeatedly proven reliability and high performance throughout the entire service life should definitely be taken into account along with other factors. Indeed, in the medium and long term, such a decision will pay for itself in full.
In the next post, we will continue the conversation about SSD drives and consider other advantages of HGST in this area.
Source: https://habr.com/ru/post/249205/
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