ioSafe Duo with TrueNAS

[HarryMuscle]

Has anyone tried using a ioSafe Duo unit with TrueNAS? I've read that some USB multi drive DAS units aren't correctly recognized with only one drive being accessible so I'm hoping someone has tried this one before I get it. This would be for backups so speed isn't a concern and having a fire and flood proof backup unit would be handy.

Thanks,
Harry

 

[Arwen]

First problem, the ioSafe Duo has a hardware RAID controller. Even if you re-configure it to be JBOD, it's likely that still hides SMART and direct disk access from the host server.

Next, USB is generally not a robust protocol for storage, unlike SAS & SATA. USB has gotten better, especially if you use higher speed connections, (like this ioSafe Duo), and if the device supports UASP, (USB Attached SCSI Protocol). But, we still discourage data disk connections via USB. (Temporary backup disks via USB can work...)

To continue, OpenZFS tends to push TONS of data through in a short time. Either writing it's transaction groups, performing pool scrubs or performing ZFS Send / Receives for backups. This tends to find corner cases and odd flaws in disk connections. SAS & SATA tends to be better, though can also be impacted by this if using cheaper, or less well tested disk host bus controllers.

Last, since this is a USB device, it may very well hide the attached disk's serial numbers. Thus, confusing the host server in determining which disk is which. So the TrueNAS server might think it has 2 paths to the same disk. (Which could lead to pool corruption very quickly.)

 

[HarryMuscle]

First problem, the ioSafe Duo has a hardware RAID controller. Even if you re-configure it to be JBOD, it's likely that still hides SMART and direct disk access from the host server.

Next, USB is generally not a robust protocol for storage, unlike SAS & SATA. USB has gotten better, especially if you use higher speed connections, (like this ioSafe Duo), and if the device supports UASP, (USB Attached SCSI Protocol). But, we still discourage data disk connections via USB. (Temporary backup disks via USB can work...)

To continue, OpenZFS tends to push TONS of data through in a short time. Either writing it's transaction groups, performing pool scrubs or performing ZFS Send / Receives for backups. This tends to find corner cases and odd flaws in disk connections. SAS & SATA tends to be better, though can also be impacted by this if using cheaper, or less well tested disk host bus controllers.

Last, since this is a USB device, it may very well hide the attached disk's serial numbers. Thus, confusing the host server in determining which disk is which. So the TrueNAS server might think it has 2 paths to the same disk. (Which could lead to pool corruption very quickly.)

While I would agree with most or possibly all of your points in general, I would use the ioSafe Duo purely for backup purposes, so the only real requirement would be: does it work. Chances are I wouldn't even be using ZFS on it (the backup software already adds redundant information that allows repairing damaged backup files).

Thanks,
Harry

 

[jgreco]

Chances are I wouldn't even be using ZFS on it

TrueNAS only supports ZFS. It isn't clear what you're thinking you're going to do that wouldn't use ZFS.

the backup software already adds redundant information that allows repairing damaged backup files

Well, if you're planning to run that in a container or virtual machine, that's fine, it could work. The question then isn't one of compatibility with TrueNAS. You can't run random backup software directly on TrueNAS (or, rather, while you might be able to forcibly install it, bad things will happen down the road).

 

[HarryMuscle]

TrueNAS only supports ZFS. It isn't clear what you're thinking you're going to do that wouldn't use ZFS.



Well, if you're planning to run that in a container or virtual machine, that's fine, it could work. The question then isn't one of compatibility with TrueNAS. You can't run random backup software directly on TrueNAS (or, rather, while you might be able to forcibly install it, bad things will happen down the road).

Since I'm dealing with external USB attached disks I would most likely go with ext4 manually mounted via the CLI since like you said I don't think the GUI will mount anything other than ZFS.

The backup software would be running in a Docker container.

Having said that, the real question is whether anyone has tried this combination before cause if the ioSafe Duo exposes the same serial number for both drives I don't believe things will work with TrueNAS ... or is that only a GUI limitation, which if I'm working with ext4 drives manually mounted might not be an actual issue?

Thanks,
Harry

 

[Arwen]

Ah, I understand now. Sorry I was a bit forceful, was just trying to describe all the issues. Some of which may not apply in your case.

It is possible that using TrueNAS SCALE with EXT4 and backup software in a container would work.


One last thing, the ioSafe Duo still may not let you run SMART tests or get detailed responses back. You may end up having to pull the disk out and use a (e)SATA or SAS port to run tests & get status information.

 

[anodos]

We've basically enabled large xattr support (up to 2 MiB) for ZFS on SCALE (for compatibility with FreeBSD), and so this may impact your ability to back up directly via CLI to ext4 (if you have written large xattrs over SMB). This may be the case with MacOS SMB clients. To be frank, this is going outside the bounds of how the product is designed.