Installing Fibre Channel LTO drives

These ATTO interfaces add FC ports to the Mac enabling control of a LTO tape drive or library

YoYotta suggests using SAS drives and libraries, both the drives and interfaces are more affordable.
SAS interfaces can connect more drives and they use more durable cables.
SAS has a simpler configuration and gives the same performance.

YoYotta can be used with Apple Silicon Macs or Intel Macs.
All macOS versions since Big Sur will need software drivers for SAS and FibreChannel interface cards and Thunderbolt LTO drives.
Thunderbolt units have a SAS LTO drive inside, so they will need a SAS driver.

ATTO Fibre Channel (FC) interfaces

FC LTO drives have 8Gb/s interfaces.
Unlike SAS each FC connector only supports the direct connection of one LTO drive.

If the drive has a Fibre Channel connection there are ATTO FC81 / FC82 / FC84 PCIe FC PCIe cards.
Use an ATTO FC card in a Sonnet Echo Express Thunderbolt3 chassis.
There are also TLFC-2082/2162 Thunderbolt2 to FC interfaces, they have 2 FC connectors so they can only control 2 drives.

TLFC-3162 and TLFC-3322 Thunderbolt 3 FC adaptors have issues with direct connections to LTO drives so they are not compatible.
A possible workaround is to use a Fibre Channel switch between the adaptor and the LTO drive. This is another reason to use SAS LTO drives wherever possible or use an older Celerity 8Gb card in a Thunderbolt chassis.

Download and install the latest Mac driver and card firmware from the ATTO website Fibre Channel HBA downloads.
Note that the ATTO multipath driver does not support tape drives.

  • Download the macOS Configuration Tool, macOS driver and macOS Flash Bundle
  • Install the Config Tool and the macOS driver
  • Run the ATTO Config Tool and update the card firmware
The PCIe card can go in a Thunderbolt expansion like the Sonnet Echo Express SEL shown here.

Here are the recommended settings in the ATTO ConfigTool.
  • Use the standard ATTO FC driver NOT the ATTO multipath driver
  • Enable Native Multipathing
If you have problems mounting or formatting tapes.
  • Maximum I/O Transfer Size – 1 MB (change from Default)

Checking hardware devices

To check that the Mac can see the ATTO and LTO hardware hold the alt key on the Mac keyboard, click the Apple Menu and select System Information...

Check for PCI devices

If using an ATTO card inside a Thunderbolt chassis, then select PCI from the left hand Hardware list. The ATTO Fibre Channel card should be shown.

Check for Thunderbolt devices

If using an ATTO card in an expansion chassis, or you have a Thunderbolt LTO drive, then click Thunderbolt. Here the Sonnet Echo Express Pro is connected to the Mac. If there is no Thunderbolt device, then try reconnecting or using a different Thunderbolt cable. Also power cycle the Mac, interface and drive.

ATTO Driver missing or blocked

Now select Fibre Channel from the Hardware list. Here the driver has not been installed so no devices are shown. On newer macOS versions the driver may also be blocked, see the next section.

If missing then download and install the Mac driver for the Fibre Channel interface from the ATTO website. Then reboot the Mac.
Note that Thunderbolt drives have a SAS tape drive and a SAS interface inside, so they also need a driver from ATTO or Areca.

Allow system software in System Security

The first time after you install ATTO drivers on a new system, you will need to approve the new System Software. Also new installs of system software from YoYotta, ATTO, OSXFUSE (developer is Benjamin Fleischer) and other drivers may need approval.
You will see a message like this saying System Extension Blocked
Open the Security & Privacy page in Apple System Preferences, unlock the padlock and click Allow to enable the System software to load.

You must click the Allow button locally on the Mac, clicking using remote screen sharing will not work.
If the Allow button is not shown then reboot your Mac, try again to use an LTFS tape (which will fail) and then check the Security & Privacy page again.
Also ensure that you have the latest macOS 10.13.6, 10.14.6, 10.15.7, 11.6.5 or latest Monterey

Files and Folders access

When running YoYotta with newer macOS versions you may see requests to allow access to folders like Documents, Removable Volumes or Network Volumes. Please allow these requests.
Also you can enable access in Files and Folders in the Security tab as shown in the screenshot.
YoYotta does not need Full Disk Access.

ATTO Driver installed

Now the driver is installed and the ATTO Fibre Channel device is shown. No tape drives are connected.

LTO drive connected

Make sure an LTO drive is connected and powered on, now a SCSI Target Device @ 0 is shown. Here an IBM LTO-5 drive is connected.
YoYotta with LTO drive support will now be able to control this drive.
The System Information page does not refresh automatically. Click File, Refresh Information or Command + R to refresh the hardware listing.

LTO library connected

Here an HPE MSL4048 with three LTO drives is connected. SCSI Target Device @ 1 has two logical units. The first is an LTO-5 drive, the second is the library robot. If two logical units are not shown then the configuration of the tape library needs to be set to allow external control. Check the settings for the control path, which are normally in the partition settings, using the library web browser interface.
SCSI Target Devices 2 and 3 are LTO-5 and LTO-4 drives.
This is a SAS library, check the Fibre Channel entry for a FC library.

YoYotta with the Library option will now be able to control this library.

FC troubleshooting

If jobs stop with errors like these, first check that the path in the error includes LTFS. If it does not then you need to check the source or destination drive, NAS or SAN.

Problem writing file 'Socket is not connected' (57)
Problem writing file 'Input/output error' (5)

These errors are low level issues sent from macOS that do not give much more information other than writing to the tape has failed.
This could be a SAS/FC interface, LTO drive or tape issue, to troubleshoot follow these steps.

  • Eject all tapes
  • Download the macOS Config Tool, driver and Flash Bundle from the ATTO website SAS downloads
  • Install the Config Tool and the macOS driver
  • Run the ATTO Config Tool, check and update the card firmware
  • Reboot the drive and Mac
  • Run test archive jobs from a local SSD to a new tape
If any issues Open the ATTO Config Tool and click Run Diagnostics in the Help menu. This will take some time to collect and save diagnostic logs.
Also save a copy of the YoYotta log + debug as described here
Then send both logs to and we will help you troubleshoot the issue.

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