Why Use Lustre™
April 1, 2011
High Performance Computing (HPC) clusters are created to provide extreme computational power to large scale applications. This computational power often results in the creation of very large amounts of data as well as very large individual files. For quite some time, the speed of processors and memory have risen sharply, but the performance of I/O systems has lagged behind.
The Lustre file system is a parallel file system used in a wide range of HPC environments, small to large, such as AI/ML, oil and gas, seismic processing, the movie industry, and scientific research to address a common problem they all have and that is the ever increasing large amounts of data being created and needing to be processed in a timely manner. In fact it is the most widely used file system by the world’s Top 500 HPC sites.
Lustre is implemented using only a handful of nodes connected to the actual storage hardware. These are known as Lustre server nodes, or sometimes as Lustre I/O nodes, because they serve up all the data to the rest of the cluster, which are typically known as compute nodes and often referred to as Lustre clients.
Lustre is used primarily for Linux based HPC clusters. Lustre is an open source file system and is licensed under the GPLv2. There are two main Lustre server components of a Lustre file system; Object Storage Servers (OSS) nodes and Meta Data Servers (MDS) nodes. File system Meta data is stored on the Lustre MDS nodes and file data is stored on the Object Storage Servers. The data for the MDS server is stored on a Meta Data Target (MDT), which essentially corresponds to any LUN being used to store the actual Meta data. The data for the OSS servers are stored on hardware LUNs called Object Storage Targets (OSTs). OST ldiskfs targets can currently be a maximum size of 512TB1PB. Since we usually configure OSS/OST data LUNs in an 8+2 RAID-6 configuration, a common LUN configuration is ten 8 16 TB SATA drives. These are the most common configurations, but some sites do use SAS or NVMe drives for their OSTs.
The Lustre architecture is used for many different kinds of clusters, but it is best known for powering seven of the ten largest high-performance computing (HPC) clusters in the world, with some systems supporting over ten thousands clients, many tens or hundreds of petabytes (PB) of storage and many of these systems nearing or over with hundreds of gigabytes per second (GB/sec) or even terabytes per second (TB/sec) of I/O throughput.
A great deal of HPC sites use Lustre as a site-wide global file system, servicing dozens of clusters on an unprecedented scale. IDC shows Lustre as being the file system with the largest market share in HPC.