Troubleshooting LTO drives

We briefly present a collection of errors and solutions that every LTO user encounters from time to time. As with any hardware, from time to time errors are also encountered by users of LTO data archiving drives.

Here are some of them and hints on how to solve them

1. “Tape has been changed to read-only by LTFS”.

This error is the LTFS software's way of telling you that something is wrong with the tape or the device. 

Whenever LTFS switches a tape to read-only mode, it happens because the tape head writing part of the drive is reporting too many write errors. This causes the LTFS software to terminate the archive with a failure, because there is an external problem that needs to be solved.

Possible causes

- defective archiving media - cassette, LTO tape - (error code 6)

- defective/dirty/worn LTO drive head (error code 5 or 6)

- outdated firmware of the LTO drive

- too high operating or ambient temperature

As for troubleshooting, the following steps should be performed in order:

Check the Single Character Display (SCD) on the front of the drive. Sometimes it is enough to insert a cleaning tape, but only if the C code is displayed. Other codes are described below.

If the LTO drive is running on old firmware, perform the appropriate upgrade and try again. The success rate of this procedure is very high, so do not skip it.

Try using a different tape, preferably from a different batch. Each tape surface has irremovable defects that often recur within the same batch, so rule this out.

If the problem persists, the next step is to perform hardware diagnostics at a specialized LTO service - such as our LTO Abart Pro service.

2 The LTO device - the LTO drive - displays an error code. What does it mean?

Each LTO drive is essentially a computer and as such executes its own instructions and handles errors. Most drives have a single-character display (SCD) that indicates the status of the device. It is located behind a black, transparent panel, so it will generally not be visible except during startup (a countdown is displayed) or when an error occurs. 

Whenever a number or letter is visible on the front of an LTO drive, the software is unable to communicate properly with the drive, and thus is unable to perform archiving on LTO tapes. Refer to the list of SCD error codes to find out how to solve the problem. Since these are hardware errors, if necessary, contact your LTO drive supplier or a qualified service center - such as our Abart Pro - to resolve the problem.

List of error codes on the LTO drive's SCD display

LTO error 0 - No error. Started successfully.

LTO error 1 - Cooling problem.

LTO error 2 - Problem with 5 V DC power supply. The tape drive has detected that the drive's power supply is approaching the specified voltage limit (the drive continues to operate) or is outside the specified voltage range (the drive does not operate).

LTO error 3 - The tape drive has detected a microcode error. 

LTO error 4 - Microcode or tape drive problem. The tape drive has determined that a microcode or tape drive hardware error has occurred.

LTO error 5 - Tape drive problem. The tape drive determined that there was a tape drive hardware failure. 

LTO error 6 - Tape drive or media error. The tape drive has determined that an error has occurred, but cannot isolate the error due to faulty hardware or tape cartridge.

LTO error 7 - Media error.

LTO error 8 - Tape drive, SCSI bus or fiber channel error. 

LTO error 9 - Tape drive or RS-422 error.

LTO error A - Hardware problem with the tape drive.

LTO error B - No error or message has been assigned.

LTO error C - The tape drive needs to be cleaned.

LTO error D - No error or message has been assigned.

LTO error J - A tape that is too new was loaded into an older generation LTO drive.

LTO error = - The cassette eject button on the drive was pressed and not released.

3 - “Media consistency check failed”.

This error means that the LTFS system has detected that the last known tape index is invalid and therefore cannot be mounted. If the mount fails due to index problems, LTFS will perform the recovery itself and then report this error if it fails.

This error is often caused by disconnection of the Thunderbolt cable from the LTO drive or loss of power. If there is no valuable data on this tape, by far the easiest way is to simply format it. If this is not possible, you can try the Repair action in LTO tape archive software. 

The Repair option, for example, in Canister software, which we offer, starts a full recovery, which can also be performed directly from the Terminal by typing the command ltfsck -f 0

After full recovery, a _ltfs_lostandfound folder will be created on the tape. LTFS will create binary files of all unreferenced data and add them to the index. This is not very useful, but it is an indicator that a rollback is necessary to access the data.

Deep data recovery is also possible. First unmount the tape, then execute the command in the terminal: ltfsck --deep-recovery 0

If none of this helps, it's time for a rollback.

Rollback

For each change on the tape, LTFS creates a new index. These are called “generations.” They should be treated as snapshots and it is possible to restore a previous snapshot. Once a working snapshot is found, it can be continued and new data can be archived on tape.

In the Terminal, display the list of rollback points. Note: this process takes time! Go for a coffee.

In Terminal, type the command: ltfsck -l 0

Create a list of rollbacks from top to bottom, starting with the newest one. Monitor the timestamps to find the desired rollback point and cancel with Command-C.

Then rollback to that generation: ltfsck -g 57 -r 0

In the example, 57 is the generation number and 0 is the drive ID. If you have one LTO drive, it is always 0.

When the process is complete, mount the tape and you will see that its contents have been restored.

4. the tape was mounted, but suddenly the lost_and_found folder appeared on the tape.

If the lost_and_found folder is visible on the tape, it means that the tape has been repaired, but without success.

When the tape cannot be mounted, LTFS will report the need for repair. If the repair process locates data in the tape's data partition that is not referenced in the index partition, it will be added as “lost and found” (lost_and_found) data. This is raw data and does not reveal file names, so for most purposes it is pretty useless. Only if you know what should be on this tape and what is missing will you be able to compare file sizes and rename files in this folder using Terminal's mv command.

In the guide above, we briefly explained the most common errors and how to fix them. In case the error cannot be fixed and everything indicates that it may be a physical damage to the LTO drive, we invite you to contact us. We provide service for LTO drives. For each repaired device, we offer a warranty of 6 or 12 months - depending on the extent of the repair.

If you are wondering whether to buy a new drive or repair a damaged one, to begin with, we invite you to contact us - specialized LTO service Abart Pro. We will determine the damage to the LTO drive, estimate the cost of repair. We will also suggest a new LTO drive at an attractive price.

If you need tapes for data archiving in LTO-6, LTO-7, LTO-8 standard or cleaning tapes - all with individual labels - you are also welcome to contact us. We offer tapes - data cartridge - LTO with personalized labels.