A couple of simple questions for a new Truenas user

[Evertb1]

Many external enclosures are not designed with ZFS in mind. They may not come with adequate cooling, even leave off a fan. So, when ZFS wants to scrub your backup disk, the backup disk gets HOT. Perhaps too hot.

I don't like the hassle of connecting and disconnecting drives. A backup that is not automated is a backup that will not be done (on time) if you are like me. However the problem with hot enclosures is avoidable by using a sata docking station with a regular hard drive.

 

[Arwen]

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However the problem with hot enclosures is avoidable by using a sata docking station with a regular hard drive.

Actually not. I had one of those SATA docking stations, (for bare drives), and without air movement, they too can allow the hard drive to get excessively hot. So hot, I could burn my finger. Even a cheesy 2" USB fan pointed at the drive lowers drive temps significantly.

The docking stations I refer to, are the ones that are a box that you plug the lower third of the drive into, for power & data. The rest of the drive sticks up. Very few of them have fans. I eventually found 2 external enclosures with fans that I like. They are listed in the resource.

 

[Evertb1]

he docking stations I refer to, are the ones that are a box that you plug the lower third of the drive into, for power & data.

Something like this? Though I don't use it much I own one. But it's branded differently. The brand I have don't offer them anymore. Anyway, it's much better then a small enclosure with maybe some enoying 4 cm fan.

 

[NugentS]

I just use a USB fan to keep the drive cool when I have to use the things. Its not something I would like to do in the long term

 

[Arwen]

Something like this? Though I don't use it much I own one. But it's branded differently. The brand I have don't offer them anymore. Anyway, it's much better then a small enclosure with maybe some employing 4 cm fan.

Yes, and with a fan it's much better than those without.

As for an actual enclosure, some funnel the fan's air over and around the drive, so that's more helpful than just pointing a fan at it. Second, some enclosures are metal, and make metal to metal contact with the edges and bottom of the 3.5" disk drive. Thus, the chassis can wick out some heat too.

 

[winnielinnie]

It is desirable to know enough of ZFS to take that backup disk to another computer and get data off. If your only other computers can't read an external disk formatted to ZFS, then it is a less useful backup method.

The good news is any modern Linux distro bootable live USB is more than sufficient. I've even successfully accessed native encrypted ZFS datasets (created and filled on TrueNAS CORE) using a Manjaro live USB. The ZFS packages (based on OpenZFS) are in the official repositories and are built against the official kernels (such as 5.10, 513, etc)

EDIT: There's no "GUI" method that I know of currently, so you do need to have some grasp on using "zfs" and "zpool" commands in the terminal.

Many external enclosures are not designed with ZFS in mind. They may not come with adequate cooling, even leave off a fan. So, when ZFS wants to scrub your backup disk, the backup disk gets HOT. Perhaps too hot.

If it's only going to be subjected to its highest temperatures during the occasional replication or scrub, is it really that dangerous to the drive within? Wouldn't it serve as a sort of make-shift "stress test" on your drive, in the same spirit as stress testing and "cooking" a new CPU to make sure that if it's going to fail, you'll catch it earlier than later?

 

[NugentS]

Based on my experience of using an HDD in one of these devices without a fan - they get very hot - too hot to be sensible. A USB fan off the same system works wonders - it just moves some air which is enough

 

[Arwen]

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If it's only going to be subjected to its highest temperatures during the occasional replication or scrub, is it really that dangerous to the drive within? Wouldn't it serve as a sort of make-shift "stress test" on your drive, in the same spirit as stress testing and "cooking" a new CPU to make sure that if it's going to fail, you'll catch it earlier than later?

In theory, except in practice a scrub might last 5 HOURS on large disks, over less than speedy USB interface.

Let's be clear, many external enclosures use USB, which as a temporary connection is fine. But, even USB 3 speeds, 5Gps, is less than ideal when compared to SATA III. I am NOT talking about the different in USB 3, 5Gbps verses SATA III, 6Gbps. No, what I mean is that the hard drives native interface is almost certainly SATA, not USB. So, the old USB Block Transfer protocol is slower, causing any long task, (like a ZFS scrub), to be even longer.

That said, USB UASP, (USB Attached SCSI Protocol), does improve things greatly. But, both sides of the connect need to support UASP, which includes the USB drive enclosure.

Having a hard drive heat up very high every backup, (my backup disks rotate every month or so), first due to a ZFS scrub. Then second due to the actual data transfer, is not something I want my backup disks exposed to.