The IBM System Storage EXN3500 expansion unit is a versatile, cost-effective, high-capacity SAS disk storage device for the IBM System Storage N series products. The EXN3500 offers a highly capable and resilient SAS technology for N series, available for attachment to nearly any N series model (except the N3300) utilizing SAS connectivity.
The EXN3500 is a 2U disk expansion device designed to support up to 24 SAS hard disk drives, allowing great flexibility for a wide range of customer environments. It may be mounted in any industry-standard 19 inch rack. The EXN3500 contains:
- Dual redundant hot-pluggable integrated power supplies and cooling fans
- Dual redundant disk storage expansion unit switched controllers
- 24 hard disk drive slots
- Diagnostic and status LEDs
Disk drive options for the EXN3500 include:
- 200 GB,
400 GB, 
800
GB, and 1.6 TB SSD - 450 GB, 600 GB, 900 GB, and 1.2 TB SAS drives.
- 600 GB and 900 GB SED SAS drives
For detailed information about the important differences between the EXN3500 and EXN1000/2000/4000 storage expansion units, see the IBM® System Storage® N series Universal SAS and ACP Cabling Guide.