mergerfs - How do you use balance pools?

So, I setup a mergerfs pool with the default option of "existing path - most free space" and ended up with it filling up the first hard drive and then giving the error of being out of space. I changed it to "most free space" but the damage is done, the one drive is filled to the limit. I tried to use the "balance pools" function but it asked for a password and then did nothing. How does this function even work? I have googled for the better part of an hour with no answers at all.

As you might guess, my experience with mergerfs and OMV in general is basically zero. I wasn't expecting this to be a Windows level plug and play experience but why are critical things just not explained at all? Any information I find on the topic is obviously ancient and outdated because they still call it unionfs and it took a while just to realize it's now called mergerfs.

This is all it says in the readme.md on the project:

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mergerfs.balance

Will move files from the most filled drive (percentage wise) to the least filled drive. Will do so till the most and least filled drives come within a user defined percentage range (defaults to 2%).

Run as root. Requires rsync to be installed.

I have rsync installed and I entered the root password when it asked for a password. This really isn't helping at all. What do I do to make this function work? It'd almost be faster to just wipe the drives and start copying everything again and it took 3 days to copy enough data to fill the one drive!

Well, I still don't know how to make the button in the gui work but I did work around it by using the command line option in Wetty. It took a couple tries to figure out that the path it wanted was the absolute path listed in the share but it's now balancing the pool.

Quote from ryecoaaron

It isn't asking for a password. That is just lines printed on the terminal for humor as a tribute (OMV does this). If you click the start button, it will just start.

What do you expect when you pick that policy? You are explicitly telling mergerfs to keep the files in the existing path. It can't balance anything unless those folders exist on the other drive(s). Read the mergerfs policy descriptions again (there is a button to take you to the docs in the plugin).

All the info you need is in the mergerfs docs which the plugin provides a link to.

What critical things? Is there something not in the mergerfs docs? Where would you expect to find this info? We are working on a wiki to help but since no one else helps, it takes a while. Remember we are volunteers with limited time.

The plugin runs this. No need to login as root and try to figure it out. As I mentioned above, your problems are caused by your policy.

What command did you use? I find it strange that it works from the command line but not from the plugin. The command isn't hard to use with a lot of parameters.

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So, I've been pranked by a reference I didn't get. I'm guessing when I tried to type the password and hit enter, I was effectively just hitting Close instead of the seemingly highlighted Start.

The OMV interface isn't terrible but it's not the most intuitive.

I'm used to default options that don't require extra work to make them, you know, work. I had no idea what those options even meant when I did an initial setup to test things. I was just following (or trying to) the youtube guide for it. The ones pinned in this forum.

I just used the basic "mergerfs.balance <dir>" command. I'm sure the GUI option would work, if I had realized I just needed to hit Start.

One thing I would like to see is an option to mark a drive for removal and have it automatically shuffle off the files to the rest of the pool, rather than having to remove it from the pool and then manually copy them back to the pool.

Quote from ryecoaaron

I feel that way about FreeNAS/TrueNAS but most users of that software would say the opposite. OMV also is very flexible which keeps it usable for advanced users. Being that flexible might make it seem not so intuitive for some.

The defaults do "work". They just didn't do what you wanted. I used to have the default of "mfs" but many complained that their files were all over the pool (which doesn't cause any problems since they are still visible in the pool). And since most people are switching to epmfs, I changed the default to that. I can't win.

If they were video, they were probably getting old. If people helped, we probably wouldn't have that issue.

I probably won't put something like this in the web interface since it could take days on some systems to run. To write a script to do it wouldn't be very hard.

I think I can turn off the tribute in code. I will do this since it is confusing to some.

Probably, the only way to make an interface everyone likes is to make one that you can completely customize and has presets to match common interfaces people are already likely familiar with. It'd honestly be a real pain to make something like that but I have spent more than a few idle hours thinking about how to make one. It's difficult because you need a balance between useful presets and in-depth customization.

I would have thought the normal "most free space" would be the more useful default but I'll admit, it was my fault for not even reading what they did.

It really is difficult to maintain an active and helpful community. That said, I do like a lot of what I see in OMV. It's why I was feeling rather frustrated when I suddenly stumbled over something simple.

You could always just put in a warning label, so people will know that removing a hard drive that way could take days. At the very least, it would be helpful if you published a script for it. I don't even know how to use Rsync. All the options I see are for scheduling regular jobs, not a one off thing.

You don't necessarily have to turn the tribute off. You could just attach a message at the end to clue people in that it's nothing serious and they should just click Start. If I see something like that and there's a clear indication of what I should actually be doing, it's my own fault for falling for it at that point. I'm not saying I wouldn't fall for it, I'm just saying I wouldn't even be mad and I definitely would have figured it out after getting it wrong a couple times.

I just wanted to note, the balance function finished execution perfectly last night, in spite of the fact the host desktop crashed rather hard. I have OMV installed in a VM with Manjaro as the host. The Manjaro host was fairly hosed, it was mostly unresponsive and I had to cold reboot the whole system to get it working again. Meanwhile, OMV was rock solid and I was even able to tell it to safely shut down from the web interface.

I now have to figure out if there's something wrong with the integrated GPU, if the cooling in it is just that bad or if this is some glitch with KDE Plasma. I googled "hdmi connection dropping and reconnecting" and got zero results that seemed even remotely relevant. Considering the fan was running rather hard and it was a bit hot, I'm thinking it's overheating just enough for the iGPU to crash. Well, this has nothing to do with OMV.

This is making me question whether there's even a point to the Manjaro host or whether I should just run Manjaro headless.

With those thoughts aside, I'm marking this solved.

Quote from ryecoaaron

The problem is they might get logged out the web interface and then wouldn't know when it was done. The system might be rebooted in the middle and then things could be in a bad state.

I'll add it to my never ending list of requests.

You could put an rsync command in the Scheduled Tasks section (not rsync plugin).

rsync -avr /path/to/dir1 /path/to/destination

I can't customize it. Either on or off. I will turn it off. It can show up other places if Volker wants people to see it.

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Thanks for the info. I'm sure I'll find the rsync command handy rather soon.

It's a shame there isn't a persistent place you could keep track of the progress but I understand how that would be a problem.

Weird, I would have thought you'd be able to edit it somehow. I actually like stuff like that, normally.