Cray, now owned by HPE, today introduced the ClusterStor E1000 storage platform, which leverages Cray software and mixes hard disk drives (HDD) and flash memory (SSD) to accommodate converged HPC-AI workloads at many scales. Cray described the new system as the final step in re-architecting its product portfolio for the exascale era. Cray also didn’t miss the opportunity to tout selection of ClusterStor E1000 for use in the first three planned U.S. exascale computers (Aurora, Frontier, and El Capitan with Cray as the prime systems contractor for the latter two).
For a company whose long-term health was sometimes questioned in recent years, Cray is riding high with prior worries about its standalone viability decisively resolved by the HPE acquisition. In a press pre-briefing, Uli Plechschmidt, director of storage product marketing, said the ClusterStor E1000 completes Cray’s product refresh – joining Cray’s Shasta architecture, Slingshot interconnect technology, and updated Cray software. He also reinforced Cray’s intent to serve a larger market.
“The exascale era is not defined by the size of the systems. It’s defined by the convergence of workloads – not just classic modeling and simulation running on the supercomputers or HPC clusters, but also methods of artificial intelligence like machine learning or big data analytics, all running on one machine. Going forward we’re going to focus on artificial intelligence joining the modeling and simulation because it’s the most disruptive workload from an I/O pattern perspective,” he said.
Cray expects new dense media packaging, a newly-designed memory controller, and new software (ClusterStor Data Services) – all tightly integrated with its system architecture – to help tame the data-flow challenge. Interestingly, the new controller uses AMD’s newest Rome generation CPU.
“To handle the massive growth in data that corporations worldwide are dealing with in their digital transformations, a completely new approach to storage is required,” said Peter Ungaro, SVP & GM, HPC & AI of Cray, a Hewlett Packard Enterprise company. “Cray’s new storage platform is a comprehensive rethinking of what high performance storage means for the Exascale Era. The intelligent software and hardware design of ClusterStor E1000 orchestrates the data flow with the workflow – that’s something no other solution on the market can do.”
The ClusterStor E1000 is the latest addition to the ClusterStor product line, which Cray purchased from Seagate in 2017. Claiming the new system is the fastest in the world on several metrics, Plechschmidt said new dense storage media packaging could deliver up to 1.6TB/s and 50 million IOPS per solid state drive rack and up to 120 GB/s and 10 PB usable per hard disk drive base rack.
Also noteworthy, NERSC (National Energy Research Scientific Computing Center) will deploy the new ClusterStor E1000 on Perlmutter as its fast all flash storage tier, which will be capable of over four terabytes per second write bandwidth. “This architecture will support our diverse workloads and research disciplines,” said NERSC Director Sudip Dosanjh. “Because this file system will be the first all-NVMe file system deployed at a scale of 30 petabytes usable capacity, extensive quantitative analysis was undertaken by NERSC to determine the optimal architecture to support the workflows our researchers and scientists use across biology, environment, chemistry, nuclear physics, fusion energy, plasma physics and computing research.”
The rise of mixed workloads to support converged HPC/AI workloads is especially challenging for the storage system. As a general rule the sequential movement of large files typical of traditional modeling and simulation is reasonably well-served by less expensive hard disk drives. Conversely, the I/O management for AI (particularly training) often requires moving large numbers of small files, accessed at random, which is best handled by more expensive flash memory.
“IDC projects that even in the year 2023 there still will be an 8X price difference per gigabyte between hard disk drives and enterprise SSD. [Although] we actually think the SSD price performance improvement will go a little bit faster,” said Plechschmidt. Balancing cost-performance issue is a moving target with data management software as important as the hardware media.
Broadly, ClusterStor E1000 is a “factory engineered solution” in which users mix and match media to accommodate the specific I/O profiles of the workloads in the workflow. It can be configured three ways (list of scalable storage units (SSU) at the end of the article):
- All Flash configuration. SSU-Fs only with up to 1.6 TB/sec (sequential read) and up to 50 million IOPS per storage rack.
- All Disk configuration. SSU-Ds only with up to 120 GB/sec and up to 10 PB usable capacity per storage rack
- Hybrid configuration. SSU-Fs as Flash pool and SSU-Ds as HDD pool in the same file system with ClusterStor Data Services software to orchestrate the data flow with the workflow in the most efficient way.
“The base rack contains at a minimum one 2U System Management Unit and one 2U Metadata Unit. To scale out, SSUs are added — at first filing up the remaining space in the base rack and then populating expansion racks,” according to Plechschmidt.
Here’s bit more technical detail from Cray literature:
“The new high-density enclosure will support 106 large form factor HDDs in 4 RU. Initially, the enclosure will support 4, 6, 10, 12, 14 and 16 TB HDDs followed by 20 TB and 24 TB HAMR drives respectively in the 2021 timeframe. The 2U storage controllers are using a single HDR/Slingshot NIC and 2x PCIe gen 4 SAS HBAs (16 lanes of 12 Gbit SAS) per node connecting to HDD enclosures. Initially, storage controller will support 1, 2 or 4 HDD enclosures. The HDD enclosure is designed as a fully redundant storage array with 2x SAS adapters and 2x fully configured side planes.
“As with current ClusterStor solutions, each HDD enclosure will support two disk pools (consisting of 53 drives each) configured with either GridRAID (when using LDISKFS) or ZFS…The main concept when configuring a ClusterStor E1000 solution is to combine flash and HDD based Scalable Storage Units to achieve the right balance between capacity and performance. The idea is to use Flash-based Scalable Storage Units (SSU-F) to achieve the peak performance and HDD-based Scalable Storage Units (D-SSU-x) composing the required usable storage volume. By combining these two volumes into a single namespace and using the intelligent software ClusterStor Data Services there no longer will be a need to overprovision a system to achieve performance.”
Cray’s new storage controller and software, ClusterStor Data Services, enable users to align the data flow with their specific workflows; in essence place the application data at the right time on the right storage media (SSD pool or HDD pool) in the file system.
Plechschmidt said, “ClusterStor Data services enables customers to orchestrate the data flow within the file system between the flex pool. There are three modes and we’re rolling them out in a phased approach”:
- Scripted Tiering. Available at launch, allows power users to have total control (command line interface) over what data gets staged to what storage media and when. Cray is providing tools to help manage the process.
- Scheduled Tiering.Expected in mid-2020, this is an automated method to promote data to flash then demote it back to HDD. “You can do it in the workload manager – a user needs to insert a couple of very simple workload manager directives and then, completely outside of the job runtime and application runtime, data gets promoted up, the job runs, and once the job completed, outside of the application runtime, the data gets demoted back to make space now for the next job.”
- Transparent Tiering. On the roadmap for the first half of 2021, transparent tiering won’t require user input. It’s completely transparent and to the user, said Plechschmidt, although presumably some level of control will be possible.
For connectivity, it’s no surprise that ClusterStor E1000 has 200 Gbps Slingshot switches on top of the rack. Cray also provides 100/200 Gbps Ethernet and InfiniBand EDR/HDR connectivity. Lustre is the embedded file system.
“We have chosen to continue to embed Lustre because it simply is the highest-performance lowest-cost parallel file system for HPC and we’re hardening that for reliability at exascale,” said Plechschmidt, emphasizing the new platform is flexible and able to “embed other file systems or emerging file systems in the future [but] we are convinced that Lustre is the right file system for the foreseeable future.”
Entry configurations of Cray ClusterStor E1000 will start at around $200,000 including three years of basic customer support. “The first early access systems are planned to ship to customers in December 2019. First customer shipment for production systems is planned for Q1 CY2020 with full production availability planned for Q2 calendar year 2020,” said Plechschmidt.