|
Many ARCserve* error situations point to problems accessing the tape drive. This may often be equally attributable to media error or hardware error. The following checklist lists the steps to be taken to eliminate the most common causes of these errors and to isolate the actual cause of the problem. If the situation persists after every item on this list has been checked, then the cause of the errors is very likely to be a tape drive malfunction that requires repair or replacement.
Media Problem or Hardware Problem?
Has the tape drive ever functioned properly, or have there been problems from the outset?
If a drive has been functioning normally for some time and suddenly begins exhibiting problems, then Media Error becomes the more likely cause, and those steps should be performed first. If the tape drive is newly installed, or has been functioning properly in another environment and is now malfunctioning, check for Hardware Error first.
Are there other devices on the same SCSI bus that are functioning properly?
If the answer to this is yes, then the problem is likely to be situated in the device itself or in the connection of the device to the SCSI bus.
1. Clean the tape drive heads.
- Most tape drive manufacturers recommend that heads be cleaned after every 20-25 hours of use. If it has been a long time since their last cleaning, or if the drive is located in a dusty environment, run the cleaning cartridge several times.
- Just because a drive is new, doesn't mean that the heads can't be dirty. Factory testing and shipping may result in it being necessary to clean the heads of a brand new drive.
2. Make sure that the media being used is certified by the drive manufacturer.
- Use DATA GRADE tapes only. Audio or Video grade tapes may damage the tape drive heads.
- Do not try to use tapes of greater capacity than those recommended by the manufacturer.
3. Try running the same job with a different tape, preferably a new one.
- It is not unheard of for more than one tape in a box or in a shipment to be defective. Environmental conditions during storage or shipping can result in an entire box of defective tapes. Take this into account when testing.
- Make sure that the tapes being used have not been stored in conditions of excessive heat, dust, or sunlight. Always store tapes in their protective boxes.
4. Make sure that all devices on the SCSI bus have unique SCSI IDs.
- Do not forget to take into account the SCSI host adapter itself, which is nearly always assigned SCSI ID 7 by default.
- Many SCSI host adapters expect to find hard drives at SCSI IDs 0 and other types of devices may not function properly when assigned to these IDs.
- If using a tape changer, remember that these consist of multiple devices within one box. Some changers utilize two (or more) SCSI IDs and others utilize LUNs, which allow several devices to utilize one SCSI ID.
- SCSI IDs for different devices may be set in one of several ways. Some have a selector, others may use jumpers or DIP switches, and others may be permanently set by the manufacturer.
5. Check that the SCSI bus is properly terminated.
- A properly configured SCSI installation must have terminators at both ends of the bus. Most host adapters are terminated by default, so be sure that the last device in the chain is also terminated.
- If there are both internal and external devices attached to one host adapter, it may be necessary to disable the termination on the adapter card if it is physically located in the middle of the bus.
- Some SCSI devices are internally terminated (which may be disabled through a jumper or a DIP switch), while others utilize an external termintator plug.
6. Check the cables connecting the SCSI bus.
- Make sure that all SCSI connections are tightly joined.
- Examine all connectors for bent pins, foreign objects or excessive amounts of dust.
- If there is a cable available that is known to be functioning properly, then try swapping it with the one on the offending device.
7. Make sure that the host adapter card is firmly seated in the slot.
- If there are problems will all devices on a SCSI bus, try moving the host adapter to another slot, if possible.
8. Check the configuration of the SCSI host adapter for the following settings:
- SCSI DISCONNECTION should be ENABLED.
- SYNCHRONOUS NEGOTIATION should be DISABLED.
- PARITY should be ENABLED.
- SCSI TRANSFER RATE should be set for 5MbSec.
This applies to:
| 
