3D XPoint – the core of Intel Optane
Optane is Intel’s brand name for the entire collection of products based on the company’s 3D XPoint memory, technology developed in partnership with Micron. Despite their variety, this type of media is the thing all of them share in common.
3D XPoint is another form of non-volatile solid-state storage that is supposed to be a lot faster and have higher endurance than traditional NAND flash. In terms of performance, it can compare to dynamic RAM (DRAM), which enables it to speed up most computing processes. However, while DRAM is temporary, 3D XPoint retains the data even after the system is powered off. And as for the price, it fits between costly DRAM and relatively inexpensive NAND.
The architecture of 3D XPoint is different from other flash solutions. And its specific design greatly simplifies operations with memory cells, enabling more efficient performance and lower power consumption, and allows more storage to be crammed into the same space. Also, 3D XPoint is less subjected to wear caused by intensive writing. These unique attributes expand the possibilities of using this technology in different types of products.
Types of Intel Optane products
The confusion around Optane is most likely caused by the fact that the products that go by this name are distinct in their essence and thus fall under diverse categories. The principal difference between them lies in the hardware and software 3D XPoint medium is combined with. It determines the role of the Optane device in the system and its functionality.
First of all, Optane can be represented by a small cache drive used in conjunction with a slower capacious storage device, like a traditional SATA hard drive. Such a cache may be integrated into a hybrid storage module, where it complements a larger NAND-based solid state drive. Apart from that, Optane can be used for permanent storage as a speedy stand-alone drive. And, finally, there are memory-focused Optane products used alongside DRAM modules.
Let’s take a closer look at each type of Optane devices and explore the ways in which they are used.
Intel Optane cache drive
This type of Optane devices was actually the first product on the basis of 3D XPoint to enter the market. It is represented chiefly by the Intel Optane Memory and Intel Optane Memory M series. Optane caching modules look identical to modern PCIe NVMe SSDs made in the M.2 form factor. They are available in relatively small capacities of up to 64 GB. The board may come pre-installed into a PC or be added as part of an upgrade.
Pic. 1. Cache drive of the Intel Optane Memory series.
Such a module is meant to operate in parallel with the primary storage of the system, for instance, a spinning HDD or a lower-speed SATA SSD. Its major role is to accelerate the computer’s performance by caching the most frequently accessed files and applications. With commonly used data stored on a fast device, daily tasks can be completed far more quickly. The maximum benefit can be expected when processing a big volume of small files.
In order to determine what has to be cached prior to everything else, it relies on the Intel's Rapid Storage Technology (RST) software and driver. The latter monitors the frequency of requests to decide which data is moved to the cache, and which is replaced when it fills up. Thus, a portion of user files and OS elements will reside on the Optane drive, without necessarily being copied to the primary storage. Meanwhile, some Optane metadata is placed at the end of the primary disk.
When acceleration is enabled, both drives are combined into a single virtual volume similar to RAID 0 and cannot be separated. The result appears in the OS as an Intel Optane memory volume with the capacity of the primary HDD or SSD.
Pic. 2. Intel Optane cache drive coupled with a regular HDD.
Turning the feature off relocates the data to the primary drive, wipes the Optane cache and deletes the metadata. The drives then show up as individual devices.
Pic. 3. Intel Optane cache drive and a regular HDD with disabled acceleration.
It is also important to note that the technology can be deployed only on a computer that complies to its rigid hardware and software requirements. These include, inter alia:
-
a compatible Intel processor;
-
a motherboard that supports Intel Optane Memory;
-
an M.2 slot that conforms to the NVMe protocol;
-
the proper BIOS/UEFI and OS versions;
-
the corresponding RST driver and software package installed.
Particular attention should also be paid to the computer’s BIOS/UEFI settings. The SATA controller mode parameter available in BIOS/UEFI must be selected as "RAID" or "Intel RST" instead of "AHCI". Changing the mode is necessary even when there is no intention to create RAID as such, since Optane Memory itself is based on a RAID-like configuration. The M.2 slot holding the cache drive must also be recognized in the system.
Intel Optane hybrid storage
Optane hybrid storage devices operate in a similar manner. Yet, the previously described Optane cache is combined with another Intel SSD on a single M.2 board. The module is usually shipped pre-built into the systems of several major manufacturers. While the Optane part of the module is based on 3D XPoint, the other drive employs the QLC NAND flash memory technology. Such a design constitutes the basis for the Intel Optane Memory H10 and H20 series.
Pic. 4. Hybrid drive of the Intel Optane Memory H20 series.
The Optane cache here is supposed to compensate for the shortcomings of QLC NAND in performance and durability. At the same time, the board occupies only one M.2 slot and a small amount of room, which allows implementing the caching feature in space-constrained gadgets, like laptops and ultrabooks.
The part of the module with QLC NAND flash is found closer to the M.2 connector. It is equipped with an SM controller, DRAM and NAND packages. The Optane side includes a small Intel Optane controller, a 3D XPoint memory package and power management components. Each part of the module has two dedicated PCIe lanes.
Pic. 5. Layout of the Intel Optane hybrid storage module.
Both drives on the module operate independently, without communicating directly with each other. The already mentioned Intel's RST (Rapid Storage Technology) driver handles all caching and makes them appear as a single unit similar to RAID 0. When acceleration is disabled, the parts of the module will be treated as individual devices.
In terms of functionality, such a configuration does exactly the same as having standard Optane Memory with a separate SSD. However, in view of its peculiar construct, even more strict system requirements must be met for it to function correctly. Besides the previously mentioned points, it needs a special M.2 slot that must support the so-called bifurcation. In order to host both the Optane and QLC NAND components, it should provide four PCIe lanes and be able to split them into two sets of two lanes each. Without due support, only the QLC NAND part of the device will be recognized.
Intel Optane stand-alone SSD
Intel also provides pure Optane SSDs that can serve as a superfast permanent storage. Such a device is basically 3DX Point memory built into the M.2, 2.5-inch U.2 or PCIe add-in-card form factor. Their capacities range from 58 GB to 3.2 TB. There are several SSD product lines aimed at the consumer market and enterprises, but these differ mostly in their prices and endurance rather than layout.
Pic. 6. Intel Optane SSD in the M.2 form factor.
Optane SSDs are very costly compared to NAND-based options, which makes them more suitable for PC enthusiasts and high performance server environments. However, their compatibility is similar to those of the majority of NVMe SSDs. With proper drivers, they can work in a wide range of systems, in contrast to other types of Optane products that are extremely picky in their requirements.
Intel Optane persistent memory
Another form Optane takes is represented by the Intel Optane DC Persistent Memory series. It brings 3D XPoint to memory sticks designed in the DDR4 form-factor. Such modules fit into DDR4 DIMM sockets on compatible server motherboards, traditionally used for volatile memory. They come in capacities of up to 512 GB, which is much higher than typical DDR4 modules of 16-64 GB.
Apparently, such a module cannot replace DRAM. Instead, it can complement the existing memory configuration with additional capacity at a more affordable cost. Although slower than DRAM, it can also enhance the overall performance through caching.
The peculiarities of data recovery from Intel Optane devices and the exact procedure performed with the help of the UFS Explorer software product are explained in the dedicated article.
The described technology is supported for data recovery and access by the following software products:
-
UFS Explorer Professional Recovery Full support
-
Recovery Explorer Professional Full support