Overview
Today's scientific research involves increasingly large volumes of increasingly complex data. At the same time, CPU performance has improved well beyond storage media, which can create bottlenecks in HPC environments. Read this section to learn how to optimize your storage usage I/O performance on Palmetto 2.
Palmetto 2 provides three data spaces: home, scratch, and group project storage.
Every user has a home directory and access to the scratch file systems. Group project storage is allocated for faculty to house their data and can only be accessed by users having the owner’s approval. Each data space is accessible from anywhere in the cluster.
Storage Hardware Grid
The table below describes each file system on Palmetto and the hardware for the storage medium and connection to the nodes.
| Name | Size | Disk Type | File System | Connection Type | Backup |
|---|---|---|---|---|---|
/home | 250GB per user | SSD | Indigo | Network (IB, ethernet) | ✅ yes |
/scratch | 5 TB per user | SSD | Indigo | Network (IB, ethernet) | ❌ no |
/local_scratch | 99GB - 2.7TB per node | HDD, SSD, NVMe | ext4 | Internal (SAS, SATA, PCIe) | ❌ no |
/project/{path} | Varies by owner | SSD | Indigo | Network (IB, ethernet) | ✅ yes |
What do the abbreviations in the storage hardware grid mean?
The legend below includes common storage-related abbreviations that may be used in the storage hardware grid or elsewhere.
| Term | Explanation |
|---|---|
| HDD | Hard Disk Drive |
| SSD | Solid State Drive |
| NVMe | Non-Volatile Memory Express |
| PCIe | PCI Express |
| PCI | Peripheral Component Interconnect |
| SAS | Serial Attached SCSI |
| SCSI | Small Computer System Interface |
| SATA | Serial ATA |
| ATA | Advanced Technology Attachment |
| IB | InfiniBand |
| GB | Gigabyte |
| TB | Terabyte |
Performance Guidelines
Generally speaking, /local_scratch will always be the fastest file system to
use because there is no network involved. However, this space cannot be shared
between a group of nodes participating in a job, and the data must be moved to
permanent storage before the job completes.
Otherwise /home, /scratch, and /project are all on the same file system.
Meaning that there is no performance difference between these different
locations on Palmetto 2.