VMA - smart flash memory for database
Last year, we already talked in detail about the flagship of the HP ProLiant line - the 8-socket DL980 , which for the first time implements the functions of business-critical systems for standard architecture servers. One of the main applications of this server is the maintenance of large Oracle databases, Microsoft SQL Server. This year, a new solution was developed on the basis of this server, which allows dramatically improving database performance through the use of flash memory.
Currently, flash memory is widely used in servers and storage systems, however, despite its obvious advantages over hard drives, it also has its own specific problems:
- Typical flash blocks are larger than typical data blocks.
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- The record must be consistent within a block of 128-256 KB
- In order to overwrite the new data in the flash memory block, you need to erase the old ones, and erasing takes a considerable time (several milliseconds) compared to the time required for the actual recording
- Data on flash memory is written more slowly than read from it.
- Due to wear, you can erase data from a block of flash memory a finite number of times.
- The risk of read errors from flash memory increases as the number of reads increases.
- Flash memory may lose data (charge flows), even if there are no hits
- Not only a block or page of flash memory, but also a whole chip can fail
To this is added the fact that the algorithms of RAID-arrays, which allow to improve the performance and reliability of storage, were developed based on mechanical hard drives.
Fortunately, not everything is so tragic, because there are arrays of flash memory, the design and firmware of which allow to overcome the above problems. HP proposes to use to improve the performance of databases running on the HP ProLiant DL980, intelligent arrays of VMA flash memory that are connected to the server via PCIe. These 3U rackmount devices use SLC single-level flash and are available in 5TB and 10TB configurations. VMA provides a constant data writing speed that does not degrade over time, and supports hot swapping of modules.
As an analogue of classic RAID, it uses the Flash vRAID algorithm, which eliminates the delays associated with the mechanics, allows you to provide up to 80% of “clean” capacity, hot-swappable flash memory modules and guarantee a storage life of 5 years even at a maximum write speed of 8 TB /hour.
We now present several characteristics of VMA performance:
One array provides a write speed of 250,000 IOPS (or up to 2,700,000 IOPS per cabinet) and throughput of 1.4 GB / s (over 12 GB / s per cabinet).
The new HP solution is capable of processing 200 million transactions per hour, while the delay is less than 100 microseconds (about 30 times less than hard drives). In addition, unlike hard drives, due to the lack of mechanical components, VMA provides a predictable delay.
Currently, flash memory is widely used in servers and storage systems, however, despite its obvious advantages over hard drives, it also has its own specific problems:
- Typical flash blocks are larger than typical data blocks.
')
- The record must be consistent within a block of 128-256 KB
- In order to overwrite the new data in the flash memory block, you need to erase the old ones, and erasing takes a considerable time (several milliseconds) compared to the time required for the actual recording
- Data on flash memory is written more slowly than read from it.
- Due to wear, you can erase data from a block of flash memory a finite number of times.
- The risk of read errors from flash memory increases as the number of reads increases.
- Flash memory may lose data (charge flows), even if there are no hits
- Not only a block or page of flash memory, but also a whole chip can fail
To this is added the fact that the algorithms of RAID-arrays, which allow to improve the performance and reliability of storage, were developed based on mechanical hard drives.
Fortunately, not everything is so tragic, because there are arrays of flash memory, the design and firmware of which allow to overcome the above problems. HP proposes to use to improve the performance of databases running on the HP ProLiant DL980, intelligent arrays of VMA flash memory that are connected to the server via PCIe. These 3U rackmount devices use SLC single-level flash and are available in 5TB and 10TB configurations. VMA provides a constant data writing speed that does not degrade over time, and supports hot swapping of modules.
As an analogue of classic RAID, it uses the Flash vRAID algorithm, which eliminates the delays associated with the mechanics, allows you to provide up to 80% of “clean” capacity, hot-swappable flash memory modules and guarantee a storage life of 5 years even at a maximum write speed of 8 TB /hour.
We now present several characteristics of VMA performance:
One array provides a write speed of 250,000 IOPS (or up to 2,700,000 IOPS per cabinet) and throughput of 1.4 GB / s (over 12 GB / s per cabinet).
The new HP solution is capable of processing 200 million transactions per hour, while the delay is less than 100 microseconds (about 30 times less than hard drives). In addition, unlike hard drives, due to the lack of mechanical components, VMA provides a predictable delay.
Source: https://habr.com/ru/post/148798/
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