A couple of months ago, Radix got the opportunity to work with the latest Seagate EXOS drives, designed for enterprise-class tasks. Their distinguishing feature lies in the hybrid drive device - it combines the technologies of conventional hard drives (for main storage) and solid state drives (for caching hot data).
We already had a positive experience using Seagate hybrid drives in our systems - a couple of years ago we implemented a solution for a private data center together with a partner from South Korea. Then the Oracle Orion benchmark was used in the tests, and the results obtained were not inferior to All-Flash arrays.
In this article, we will look at how Seagate EXOS drives with TurboBoost technology are arranged, evaluate their capabilities for corporate segment tasks, and test performance on a mixed load.
Tasks of the corporate segment
There is a more or less stable range of tasks that can be designated as data storage tasks in the corporate (or enterprise) segment. These traditionally include: the functioning of CRM applications and ERP systems, the operation of mail and file servers, backup and virtualization operations. From the storage point of view, the implementation of such functions is characterized by a mixed load flow, with a clear predominance of random requests.
In addition, such resource-intensive areas as OLAP (Online Analytical Processing) multidimensional analytics and real-time transaction processing (OLTP, Online Transaction Processing) are actively developing in the enterprise segment. Their peculiarity lies in the fact that they rely more on read operations than on write operations. The load they create - intensive data flows with a small block size - requires high performance from the system.
The role of all these functions is growing rapidly. They cease to be auxiliary blocks in the processes of value creation and move into the section of the key components of the product. For many forms of business, this is becoming an important component of building competitive advantage and market sustainability. In turn, this significantly increases the requirements for the IT infrastructure of companies: technical equipment must provide maximum throughput and minimum response time. To provide the necessary performance in such situations, choose All-Flash systems or hybrid storage systems with the function or tiring.
In addition, there is another factor characteristic of the enterprise segment - stringent requirements for economic efficiency. It is quite obvious that not all corporate structures can afford the acquisition and maintenance of All-Flash arrays, so many companies have to give up a little in performance, but purchase much more cost-effective solutions. These conditions strongly shift the market focus towards hybrid solutions.
Hybrid principle or TurboBoost technology
The principle of using hybrid technologies is now well known to a wide audience. He talks about the possibility of using different technologies to obtain additional benefits in the final result. Hybrid storage combines the strengths of solid state drives and classic hard drives. As a result, we get an optimized solution, where each component works with its own task: the HDD is used to store the main amount of data, and the SSD is used for temporary storage of βhot dataβ.
According to , in the EMEA region, hybrid storage accounts for about 45.3% of the market. Such popularity is determined by the fact that, with comparative performance, the cost of such systems is significantly lower than that of SSD-based solutions, and the price for each IOps lags behind by several orders of magnitude.
The same hybrid principle can be implemented directly at the drive level. Seagate pioneered this idea with SSHD (Solid State Hybrid Drive) media. Such discs have gained relative popularity in the consumer market, but they are not so common in the b2b segment.
The current generation of this technology at Seagate is commercially known as TurboBoost. For the enterprise segment, the company uses TurboBoost technology in the Seagate EXOS line of drives, which have increased reliability and an optimal combination of performance and economy. The storage system assembled on the basis of such disks will, according to the final characteristics, correspond to a hybrid configuration, while caching of βhotβ data occurs at the drive level and is performed due to firmware capabilities.
Seagate EXOS drives use a built-in 16 GB eMLC (Enterpise Multi-Level Cell) NAND memory for local SSD cache, which has a significantly higher rewrite resource than consumer-segment MLC.
Joint utility
Having at our disposal 8 Seagate EXOS 10E24000 1.2 TB drives, we decided to test their performance in our system based on RAIDIX 4.7.
Outwardly, such a drive looks like a standard HDD: a 2,5-inch metal case with a branded label and standard mounting holes.
The drive is equipped with a 3 Gb / s SAS12 interface, which allows you to efficiently work with two storage controllers. It is also worth noting that this interface has a greater queue depth than SATA3.
Note that from the point of view of management, such a disk in the storage system appears to be a single medium in which the storage space is not divided into HDD and SSD areas. This eliminates the need for a software SSD cache and simplifies system configuration.
As an application scenario for a ready-made solution, work with a load from typical corporate applications was considered.
The main expected benefit from the created storage system is the efficiency of work on mixed loads with a predominance of read operations. RAIDIX software-defined storage delivers superior serial load performance, while Seagate TurboBoost drives help optimize random demand.
For the chosen scenario, it looks like this: the efficiency of working with a random load from databases and other applied tasks will be guaranteed by SSD elements, and the specifics of the software will allow maintaining a high speed of processing sequential loads from database recovery or data loading.
At the same time, the whole system looks attractive in terms of price and performance: inexpensive (relative to All-Flash) hybrid drives are well combined with the flexibility and cost-effectiveness of software-defined storage built on standard server hardware.
Performance testing
Testing was carried out using the fio v3.1 utility.
A sequence of minute fio-tests, 32 threads each, with a queue depth of 1.
Mixed load: 70% read and 30% write.
Block size from 4k to 1MB.
The load on the zone is 130 GB.
Server platform
AIC HA201-TP (1 pc.)
CPU
Intel Xeon E5-2620v2 (2 pcs.)
RAM
128GB
SAS adapter
LSI SAS3008
Storage devices
Seagate EXOS 10E24000 (8 pcs.)
Array level
RAID 6
Test results
A system based on RAIDIX 4.7 with 8 Seagate EXOS 10e2400 drives shows a total performance of up to 220 IOps per 000k read/write block.
Conclusion
Drives with TurboBoost technology open up new possibilities for users and manufacturers of storage systems. The use of a local SSD cache greatly improves system performance without significantly increasing the cost of purchasing drives.
Seagate drives tested in showed a confidently high level of performance on a mixed load pattern (70/30), simulating the approximate requirements of applied tasks in the corporate segment. At the same time, indicators were achieved 150 times higher than the limit values ββ\u60b\uXNUMXbof HDD drives. It is worth noting here that the cost of purchasing storage systems for this configuration is about XNUMX% of the cost of a comparable All-Flash solution.
Key indicators
- Drive annual failure rate is less than 0.44%
- 40% cheaper All-Flash solutions
- 150 times faster than HDD
- Up to 220 IOps on 000 drives
Source: habr.com