btrfs + mergerfs or btrfs single.

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btrfs + mergerfs or btrfs single.

Postby delina » 2018-12-31 06:24

I have been attempting to make a large single drive using either btrfs in single mode or a mix or btrfs and ext4 with mergerfs.

so far the mix of btrfs and mergerfs seems to fail as the merged drive seems to keep unmounting after a hour or more.

I build a box to test the single with 8 drives but had a power supply failure before i could see how that works.

does anyone have any ideas which works.

Im thinking of scraping this idea and going back to just ext4. I was hoping to use the compresson and dedupe features of the two.
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Re: btrfs + mergerfs or btrfs single.

Postby pylkko » 2019-01-01 10:26

For myself, I can say that I do not understand at all what you are trying to do, why and what your question even is to be exact.

Do you want to combine several physical drives to a storage pool? I hope you realize that this is a feature in btrfs itself and you don't need mergerfs for that purpose. Or did I misunderstand what you want?

If your mergerfs gets unmounted, what message does it report in the logs?
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Re: btrfs + mergerfs or btrfs single.

Postby delina » 2019-01-02 13:13

i have lots of drives in a pool with mergerfs now I have created 1 drive as a btrfs and added it to the pool but btrfs seem strange it does not behave like a regular drive. it seems to be there and disappear some times like it goes offline when system is doing things.

--mostly im not trying to create a high performance or a raid or such. I keep a lot of not important files for a period of time and need lots of space. I wanted to use btrfs if i can get it all to work for the compression and the dedupe features.

I made a box with 8 2 tb drives into a 16 tb as single then I removed 1 drive and the whole array goes offline but there is no warning messages when this happens. I suspect this would take some custom coding to get the messages.

I have been trying to find some site were more people have created media pool for home use like this. Raids and such just wear the drives out so fast I rather have them setting idle and not doing much. I am kind of worried about using btrfs to create large single drives after reading that if one dies you will loose all the drives as it does not seem to keep the directory on each drive or metadata as they call it. I think they really need to rethink this and make the single drive array so it can withstand any drive being removed and every drive survive. that is what single means to me.

I think i may just have to make each drive btrfs and just never combine them into an array. Its just to expensive to add enough drives to make it into a raid and drives rarely last 5 years any more i have a pile of dead 2 and 3 tb drives.

I cannot find much info on btrfs and there does not seem to be a real support forum for it. From what i can tell this btrfs is really different than a partition. The os seems to need a gui console for it that gives a visual feedback of what it is doing when it just goes away for long periods of time. Im not very smart at linux but dont care for most linux builds and have sort of cobbled together my own version of debian for a server from a minimal network install.
I have looked at lots of custom linus appliances to build nas boxes but they all seem to want to force you to use raid of some sort if you want to use the utilities that comes with them. So i have been just gathering bits and pieces and creating my own that allows all the drives to be independent. I have run my system like this for 20 years and it works ok I keep it all on a ups power backup and in a low vibration area of the house. all my drives are 3 4 5 6 8 12 tb on the main box. i'm trying to replace all the smaller drives as they are getting older. I'm thinking of creating large single drive arrays from the smaller drives i remove and use them to backup the remaining larger drives now and then. I am creating 5 drive groups of esata drives so i can move them to what ever machine i need. I hoped to use btrfs as single on them but worry about all data being lost if 1 drive fails. there is the possibility of going raid 1 and giving up 1 drive of the 5 for better data also. I am wondering if i create these drives can i migrate them to another machine with no problems also.

I really like the idea behind btrfs and would like to get a gui for it but I do not see one out there. It looks like it should be possible to create.

One of my biggest gripes is the btrfs commands are just a bit confusing. like if i type btrfs status i expect it to reply with something by default. it seems the developers like to make you type 3 4 or more words to get any response from it.
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Re: btrfs + mergerfs or btrfs single.

Postby delina » 2019-01-04 07:42

What a pain i got it to work finally i created 8 btrfs drives and gave each a label like drive1 drive2.... drive 8

I was trying to figure how to do this all in the gui so i used the disk utility to create the mount for the drives
it only kind of works with btrfs. to make it work i had to trick it.

i had to click change mount options then change to by label drive1
i would copy the path /mount/drive1
then change it to UUID=...... then in this setting i would replace the uuid path with the label path.
on the line that says nosuid,nodev,nofail add a ,compress and change filesystem time from auto to btrfs.

when done it makes a fstab with
UUID=xxxxxxxxxxxxxxxxxxxxxxxxxx /mnt/drive1 btrfs nosuid,nodev,nofail,compress 0 0

make sure to create folders in /mnt for drive1 drive2.. 8

then it will mount all those in those folders.

then you just make the mergerfs mount
/mnt/drive* /mnt/driveshare fuse.mergerfs minfreespace=20g,defaults,allow_other,direct_io,use_ino 0 0

i used the disk utility and set all the drive to mount on start and not be visible.
you shouold end up with a /mnt/driveshare that has the sum of all 8 drives in it.
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