Hobadee

Ah! Thanks! That needs to bubble up on Google searches better... In case anyone else needs to know, it appears you need to set the advanced option "disk.EnableUUID" to "TRUE".

For the record, I did some testing and you can in fact import existing BTRFS volumes, with some restrictions. First of all, the volume can't be part of a RAID; it appears that unRAID will just do a regular mount, and if the volume is degraded a regular mount will fail. The second restriction is that the data won't be put into a share. The data will remain in the root of the drive and you will need to manually add it to the share. This is an easy `mv` command from the command line, but it is a manual step.

So after some work, I've finally gotten unRAID to boot fine in ESXi using Plop. The issue I'm having now is seeing the virtual drives I have created for it. (My end goal is to use raw device mapping.) When I setup the drives using a LSI Logic SAS SCSI controller (from ESXi) they appear in unRAID under Tools->System Devices, but they aren't available to add to the array. Additionally I can access them without issue from the command line. If I add them to the VM as IDE drives they are able to be added to the array, but this limits me to just 3 drives. (One of the IDE devices needs to be a virtual CD for Plop to work.) I've read plenty of threads of people using raw device mapping in ESXi with unRAID, but those threads are from old versions of unRAID and ESXi. Is something eluding me or has some new restriction been put in place? I'm on ESXi 6.5 and unRAID 6.2.4

@Helmonder: We are going to run everything through cache, although I just noticed that the cache is only setup to dump once every night in a cron job; that won't work for us as we will be dumping several TB simultaneously and not leaving the server on overnight most likely, so I'm going to need to look into changing that. (Basically go to a site, backup quite a few very large files, leave site for another site.) @tdallen: No, we need parity. In fact, we will probably do dual-parity. With the size of the array I'm looking at doing, I would probably do triple-parity if possible.

I understand the technical differences between unRAID and real RAID, but in my mind 1 parity disk = RAID-5. It's easier to think about that way. :-P I've been following BTRFS for a while now and it seems to be getting to a point of decent maturity where I'm not afraid to use it. The data I'm storing is mostly my movie collection, which would be a PITA to loose, but not the end of the world since I can just re-rip it. I have no problem being a BTRFS guinea pig. With all that in mind, would a migration be possible?

I was going to try this in a VM, but I can't get unRAID to boot in VirtualBox... :-/ I currently have a server with 2 disks formatted BTRFS in a RAID-1 array. (The RAID array is through BTRFS' native RAID functionality.) I would like to migrate to unRAID. I have a 3rd disk I'm going to make a parity disk and would like to convert the existing RAID-1 disks to RAID-5. Can I easily import my existing disks (and data!) to unRAID and change the RAID level? How would I go about doing this?

A UPS doesn't work for our application; it would be a mobile server which would be regularly packed up in a truck and shipped to other locations. (It would actually be on a UPS during use, but the UPS itself would be shut off during transit.) All the writes should be complete when the power is yanked; it's a small number of very large files, not a DB or random-access application. If unRAID flushes its write-cache quickly it shouldn't be an issue, but if it lingers onto the write cache that could become a problem. When I'm the one operating it, I will do a proper shutdown procedure, but I can see other people just turning it off, which is why I asked this question.

I created an account to ask a question, but saw this and need to answer. RAID (in any form) is just a protection against hardware failure. It is NOT a backup against disaster! If there is a fire, robbery, hacker, ransomware, delete-button, etc, YOU WILL LOOSE YOUR DATA! For your photos and other irreplaceable data, GET A BACKUP SERVICE! Make sure your data is stored offsite, safe from natural disaster and software issues. Personally I'm partial to CrashPlan (which happens to be a docker container for unRAID I saw) but there are several other good ones out there as well.

How well does unRAID handle it's power being yanked on a fairly regular basis? Does the RAID write-hole exist? I ask due to a corner use-case we have, which I hope unRAID can fill, but the probability of frequent unclean shutdowns is high and unavoidable.