Key Approaches to Selecting High-Performance All-Flash Storage

With the growing popularity of All flash, strong storage performance features are becoming more and more intensified. Features such as storage systems latency shortened from milliseconds to microseconds, also indicate that the All-Flash market is more competitive than ever. 

Huawei Jul 12th 2018

With the growing popularity of All flash, strong storage performance features are becoming more and more intensified. For example, 100,000 IOPS was considered very high in 2008, but now even 10 million FA IOPS is a performance that many vendors claim to offer. Other features, such as storage systems latency shortened from milliseconds to microseconds, also indicate that the All-Flash market is more competitive than ever. 


Understanding the fine print of Storage Performance Promotions
The storage industry continues to witness many advancements and it is important to know and be aware of the product features being offered before an investment is made in the latest All-Flash products.   

1. Use performance with a 100% cache hit ratio:
When promoting storage performance, it is often mentioned "100% cache hit" in the remarks. This means that all data is stored in the memory, instead of being stored permanently. The criteria to decide a high-performance IT architecture is to check whether it stores the most frequently accessed data to the place with the fastest response.


As shown in the figure above, hot data at L0 to L2 layers is scheduled by the operating system's CPUs, while data at L3 to L4 layers is scheduled by the storage system. This is to say that it is almost impossible to have a 100% catch hit ratio in customers' environments. Because All -Flash storage applies to not only different industries but also to varying business models within in the industry. 

2. 100% read performance
Mainstream SSDs offer high performance in data reads, but their write performance is lackluster because each time data is written, SSDs erase data from a NAND before writing new data. This process is called "Program/Erase", which takes 1ms to 2ms in MLC/TLC NAND flash, leading to huge performance differences in data reads and writes.

SSDs often reserve a large amount of over-provisioning space and the "Erase/Program" process is not required every time when data is written. Generally, SSD performance deteriorates in read and write, and read-only scenarios. Therefore, real-life performance value must reflect in the customers' business models, instead of just using the value of 100% read performance. 


3. Performance stability
Often for the All Flash Storage products only reference value is promoted using a specific model and under certain pressure, rather than showing overall stability.


The stability of storage performance is critical, especially when service pressure changes and in complex service environments. When choosing storage SLA, customers regard stability as one of the most important indicators, so vendors who produce limited results are misleading their customers. 

Stability indicates that response time of 99% services must maintain under a certain value. If services fluctuate, user experience will suffer. However, most customers are unaware of this factor.

SPC, the Most Commonly Used Third-Party Storage Performance Evaluation Platform
Test standards (especially SPC-1 test for random IOPS effectiveness) proposed by the Storage Performance Council (SPC) are a common reference for measuring storage products' performance in the industry. Mainstream vendors such as EMC, NetApp, Dell, HPE, HDS, Huawei, IBM, and Fujitsu have participated in the SPC tests and used test results to promote their products' performance and cost effective features. This makes SPC-1 a well-known indicator for measuring the performance of products from various brands. 


The test specifications of SPC-1 are strict and fair. Its test program prevents deliberate data value manipulation and its test models are similar to mainstream transaction workloads, meaning SPC-1 is a reliable reference to reflect real-life application environments. 
1. Service type: For production services, the SPC provides the SPC-1 benchmark test guide. For data analysis services, the SPC provides the SPC-2 benchmark test guide. 
2. Hybrid service workload: In the SPC-1 test, multiple service workloads are used for concurrency testing to verify response times of storage systems in hybrid service scenarios. Main indicators include different data types (text, binary, and sparse), different block sizes (8 KB to 128 KB), and different read/write ratios, such as sequential reads and writes or random reads and writes. 


3. Varying service pressure: The SPC increases and decreases dynamic workload behaviors to test storage performance of varying service pressure. Specifically, the SPC starts the test from the peak value before gradually decreasing and then increasing service pressure. Then, it simulates two service peaks as shown in the following figure. 


Huawei's OceanStor 18800F V5 has achieved outstanding results in SPC-1 tests. 
1. Performance value and latency in different pressure scenarios: The OceanStor 18800F V5 has a maximum performance of 6 million IOPS and a latency of shorter than 1 ms.


2. Response time stability: Statistics show that 99.984% I/O responses are within 1 ms.


Huawei OceanStor F V5, Groundbreaking High-Performance All-Flash Storage

Equipped with OceanStor V3 converged storage systems rich with enterprise-class features and high-availability ratings. Huawei's OceanStor F V5 All-Flash storage takes performance and integration to the next level with specifically designed architecture. Huawei’s newest offerings provide organizations with a complete data management solution for their critical services and leverage built-in optimizations to enable All-Flash, all-cloud, and All-Intelligence strategies. The mid-range and high-end offerings extend to Huawei's Flash portfolio, adding to those able to meet even broader range of customer requirements. 

Huawei is committed to providing continuously higher performance and reliability to its storage customers to meet ever-escalating demands from the application environments at organizations of all sizes. Huawei Storage has broken records in SPC-1™ performance testing since 2010. The OceanStor 18800F V5 is the latest offering to break away from the pack, demonstrating the immense advantages of the intelligence-infused flash storage under scrutiny of industry testing. 


The OceanStor F V5 uses innovative self-developed flash end-to-end architecture (including multi-core CPU optimization), and leverages adaptive cache and self-developed SSD algorithms to achieve in-depth integration of system software and hardware. Its superior performance provided by an All-Flash storage helps deliver superb user experience, helping core business easily embrace the era of all-flash storage. 

This storage system uses next-generation self-developed SSD controller chips with high performance to work with new-generation efficient patent algorithms, providing users with reliable and high-performance SSD drives. Equipped with self-developed dedicated controllers, industry’s-leading system architecture, and multi-controller processing architecture with load balancing, the OceanStor F V5 provides powerful All-Flash processing capabilities and fully meets algorithm-processing requirements of the systems. Moreover, advanced processor resource allocation algorithms, LDPC error correction algorithms, and RAID 2.0+ technology achieve longevity of SSDs and fast I/O response, unleashing the full potential of All-Flash storage. 

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