How can I troubleshoot time-out errors with SCSI drives?

Configuration and troubleshooting time-out errors with SCSI drives.

Troubleshooting and Configuration Tips for SCSI Time-Outs

Configuration Tips

  • Do not mix slow and fast devices on the same bus.
    Keep slower devices such as optical drives and tape drives on a separate bus from the hard drives.
  • Confirm SCSI disconnect is enabled for all devices.
    If a device requires SCSI disconnect be disabled, then keep it on a separate host adapter.
  • Adapters that convert from an 80-pin drive interface to a 68-pin cable interface are often found to be a cause for errors on the SCSI bus.
    Purchase the appropriate interface for your configuration. The 80-pin SCA connectors are designed to be used with a backplane, while 68-pin drives are available for customers using cable configurations.
  • Confirm you are using the correct cabling.
    Ultra320 Seagate hard drives can operate at burst transfer rates up to 320MB/sec. However, to function properly at such high speeds, the cables, drive, and host adapter (SCSI card) all need to support these speeds. If the host adapter and the drive both support these speeds, then the two may negotiate to a speed higher than the cables can handle, which can cause errors such as time-outs.
  • Determine if more than one drive is affected.
    If only one drive is affected it may be a setting or jumper on the drive. If several drives are reporting the error it is more likely the cabling, termination, or a setting on the host adapter.
    If only one drive is affected, then run SeaTools Enterprise on that drive to determine if the drive is defective.

Troubleshooting Tips

  • If using other devices on the host adapter (not recommended), then give the slower devices, such as CD Burners and tape drives, a higher SCSI ID. For troubleshooting, temporarily disconnect these other devices to see if the time-outs continue.
  • Confirm you have up-to-date drivers and BIOS for your SCSI card.
  • Confirm you have the latest firmware for your SCSI drive (contact technical support with your model number, part number, and current firmware level).
  • Lower the transfer rate on the drive. If lowering the transfer rate fixes the issue, then it is recommended that the cable and terminator be replaced.