Balancing Act: Low-Latency Media Is a Perfect Match for High-Bandwidth CPUs

Optimize your workloads by balancing the high bandwidth of modern CPUs with low-latency Intel Optane media, deployed either as SSDs or persistent memory modules

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Intel

Database admins frequently ask: Why haven’t storage technologies kept up with processor gains?

Modern multi-core CPUs can process data faster than most storage technologies can read or write that data, creating a bottleneck in overall performance.

Over the years, CPU performance has steadily improved in lock step with Moore’s Law. But storage latency hasn’t improved at the same rate, making drives the weak link that degrades the performance of the entire system. CPU cycles are wasted as processors are stuck waiting each time additional data is transferred to or from the storage media.

Essentially, the problem comes down to an imbalance between bandwidth, which is the amount of data that can be accessed or processed at one time, and latency, which is the amount of time it takes for a given amount of data to make the trip from source to destination. Ideally, you want a perfect balance between bandwidth and latency so that no part of the system becomes a bottleneck and data-hungry processors can be more fully utilized.

A New Balance

Meet the solution. Intel Optane media significantly decreases latency for storage, so the entire system can reach its potential for processing data faster.

One way Intel Optane media can be deployed is as PCIe NVM Express (NVMe) storage. Intel Optane DC SSDs offer an average idle latency of about 10 microseconds, compared with more than 80 microseconds for NAND SSDs, as shown in Figure 1.1 That low latency makes these SSDs ideal for fast caching or tiering of hot data.

Intel Optane media can also be deployed as Intel Optane DC persistent memory, available on modules that plug into DIMM slots. Intel Optane DC persistent memory boasts an average idle read latency between 100 and 340 nanoseconds (ns).2 This form factor offers persistence and large-capacity memory—up to 512 GB per module.

infoworld content a blog image2Figure 1. Comparison of average idle read latency for NAND SSDs, Intel Optane DC SSDs, and Intel Optane DC persistent memory1,2

Filling the Capacity and Performance Gaps

There are several ways in which businesses can take advantage of the high performance and low-latency characteristics of Intel Optane media to fill system gaps in capacity and performance. For example, Intel Optane DC persistent memory can be used to significantly increase capacity for in-memory databases. And because persistent memory is non-volatile, data does not need to be reloaded from disk after a database restart. Businesses can also use Intel Optane DC SSDs for fast caching, as an alternative to costly, limited-capacity DRAM, or to significantly expand VMware virtual machine (VM) density on high capacity, low latency storage.

For a deeper look into how Intel Optane media helps balance bandwidth and latency to achieve optimal system performance, see Intel’s technical marketing brief by Frank T. Hady, Ph.D., Intel Fellow:  “Restoring the Balance Between Bandwidth and Latency."

1 Results based on Intel testing on July 24, 2018. Average read latency measured at queue-depth (QD) 1 during 4K random write workload. Measured using FIO 3.1*. Common configuration: Intel® 2U Server System, CentOS 7.5*, kernel 4.17.6-1.el7.x86_64, 2 x Intel® Xeon® 6154 Gold processor at 3.0 GHz (18 cores), 256 GB DDR4 RAM at 2,666 MHz. Configuration: 375 GB Intel® Optane™ SSD DC P4800X and 1.6 TB Intel® SSD DC P4600. Latency: Average read latency measured at QD1 during 4K random write operations using FIO 3.1. Intel® Microcode: 0x2000043; system BIOS: 00.01.0013; Intel® Management Engine (Intel® ME) firmware: 04.00.04.294; baseboard management controller (BMC) firmware: 1.43.91f76955; FRUSDR 1.43*. SSDs tested were commercially available at time of test.
2 Intel Optane DC persistent memory: results based on Intel testing on February 20, 2019. Configuration: Intel LBG B1 chipset, 28-core Intel Xeon Scalable processor (QDF QQYZ), 2,666 megatransfers per second (MT/s), 256 GB, 18 W, 32 GB DDR4 DRAM (per socket), 128 GB Intel Optane DC persistent memory (per socket), firmware: 5336, BIOS: 573.D10, WW08 BKC, running Linux 4.20.4-200.fc29. Spectre/Meltdown patched (1, 2, 3, 3a), performance tuning quality of service (QoS) disabled, IODC=5(AD).
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