This is disk a mdraid member

Hi, i’m currently running OMV on my HP Proliant Microserver gen8.
I am looking into switching the os to Rockstor.
However, data is stored on a raid0 config with the ext4 filesystem.
I’ve installed Rockstor on an external USB HDD, but i don’t know how to restore that raid0 settings.
Can i accomplish that without data lose? or the only way to do this is to back everything up and than recreate the raid0?

@jimhu Hello again and I don’t think you have yet had your customary “Welcome to the Rockstor community” so there you go. From the thread title I’m assuming you’re data disks are in an mdraid array. Rockstor only uses whole disk (non partitioned) btrfs as it’s data disks and only btrfs raid types and the sparse support for mdraid is only for the system disk. So I think the answer to your question is that you will first need to back this data up (good idea anyway) then start fresh with creating btrfs pools and shares and copy the data back.

Also note that your current install may well be affected by the following issue:

I hope to have a quick look at that issue shortly after I’m done with my current pull request but that also depends on a few other priorities I’m afraid. But there is a workaround contained in that issue once you have all your data backed up that will allow prior mdraid members to be used as fresh whole disk btrfs data disks in Rockstor.

Hope that helps.

You can of course add other drives and establish them as btrfs data disks with shares from within Rockstor WebUI and then manually copy the contents of your existing mdraid array over but this copying would all have to be done from the command line akin to any CentOS 7 system and you may then run into permission issues but this is all sortable. There are plans to improve this process though, although they are a little way off just yet I expect.

Let us know how you get on and remember that there are some pointers to general Rockstor use in the Official Documentation. Do feel free to suggest issues that can be added to the rockstor-doc repo.

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I think it would be great if Rockstor can also support other filesystems that CentOS natively supports. It may encourage more people transfer from other nas system to Rockstor.

@jimhu I agree with regard to such things as backing up or importing and there is an open issue to address this:
from within the UI. It can already be done via the regular CentOS command line means of course.

But Rockstor’s primary filesystem focus is on btrfs, introducing other file systems as main data drives would add a great deal of complexity both to the UI and the underlying support mechanisms.

Hope this helps and thanks for chipping in ideas.

I binged (sorry can’t visit google from china), and found out that converting ext4 to brtfs was not that difficult.
So maybe Rockstor can support the converting so that other adopters can switch to Rockstor easier without the risk of data loss.

@jimhu Thank’s for that but just as a note on this I’m pretty sure that the convert utility has some what fallen into disrepair and is not currently advised. I think the current thinking is that it produces non sane or problematic results. Which is a shame really because as you say it would be a neat idea / addition.

Definitely worth considering in the future if the convert utility gets to be considered safe, I think there is current activity on improving it so that’s promising. I don’t expect it to be ready for quite a while though but don’t know myself.

You are welcome to opening an issue over at rockstor-core GitHub as a feature request but I think a forum thread dedicated to getting feedback on this idea would be a better move for the time being. That way the health of the convert utility can be assessed by our community first prior to adding such a facility.

Another problem here would be no partitions on data disks and given ext4 requires a partition we would have an issue even once the conversion took place.

Thanks for bringing this up though as I don’t remember it coming up before on the forum.