Diagnosing storage bottlenecks

System-level I/O diagnostics:

iostat -x 1                         # Per-device I/O stats, 1-sec interval
iotop                               # Per-process I/O usage
dstat                               # Combined system stats

# Lustre filesystem
lfs df                              # Filesystem usage
lfs df -h                           # Human-readable
lfs setstripe -c 4 /path/to/file    # Set stripe count across 4 OSTs

Signs of a storage bottleneck:

• High I/O wait time (%iowait in iostat or top)
• GPU utilization drops while data is loading (GPU starved)
• Training throughput limited by data pipeline, not GPU compute