Hi everyone,
I had Netgear's ReadyNAS NVX (4 HDDs) NAS serving me well for the past 10 years, but recent voltage surge fried my UPS and it turned out that it fried my NAS behind it as well. I had a few minor incidents before, when individual HDDs died, but that's expected, so they were replaced and RAID re-built with no problems. This was the first time that NAS hardware died and I sent it to a service. It was originally bought in UK, while I was living there, but there is no distributor and service available in the country I'm living in now, which made me very concerned if I would be able to recover my data and thinking about switching to some other NAS solution.
As I gradually started switching my life into digital, all my family photos and family videos were on NAS, my ripped CD collection (in FLAC format), documents, ripped DVDs etc.). I had back-up on external disk, but I'm not sure how to access data as it's unreadable when connected to my Windows PC. While it was connected to NAS, it was accessible though it and perfectly readable.
Fortunately, it turned out that it wasn't NAS motherboard, but power supply that got fried, so a friend managed to make some temporary replacement and I managed to power up the NAS and access the data, then it started overheating so we opened case and added some fans to keep the temperature under control, but that's just a temporary solution. I powered it down and the plan is to build new NAS and move data to it over the network, while the old NAS is still working.
I realised that I have a long journey in front of me, where I will need a helping hand to guide me through many decisions I'll have to make, so I decided not to rush and go step-by-step instead, documenting everything through this post, hoping it will help others who go through similar process.
The first decision I had to make is whether to choose some ready made NAS solution like NetGear's, Qnap's, Synology's, D-link's etc., or should I build one from PC hardware.
Having experience I described at the beginning of this post, I wanted to avoid finding myself again in the position that I don't have replacement hardware easily available and my data locked in some proprietary software. Recovery from such systems relies on paid support and buying new proprietary hardware, which is expensive.
Therefore, the first decision is already made and I went for building new NAS from PC hardware. It was also a good excuse for buying new PC hardware as I could use the old one for new NAS 
. Looking that way, I got hardware for free .
Then I needed to decide, which NAS software to use, and obvious contenders were FreeNAS, Nas4Free and OMV if we put aside some less known solutions.
As my old PC had 4 GB RAM and all slots filled, and FreeNAS needs 8 GB RAM min. the choice was easy, and I went for OMV.
But before I go any further I would like someone experienced to re-assure me that what I would like to achieve is achievable with OMV.
So here are my lists of features, one with absolutely essential features, and the second with nice-to-have features.
Essential features:
1. in case that motherboard, OS drive or any other piece of hardware dies it should be possible to build new NAS machine with different hardware and move disks with data to it and continue using it. That procedure should be relatively simple with no much CLI commands and hacking as I'm not too familiar with linux.
2. it should be possible to use USB drive as OS drive plus 4 SATA HDDs for data.
3. it should be possible to create redundant volume out of those 4 disks, so if one disk fails, no data is lost, and when new disk replaces the failed one, redundancy is restored.
4. the disks in raid array don't have to be of the same size, so if I wan't to upgrade storage space, I don't have to buy 4 new disks.
5. if I wan't to increase the storage, I can buy larger disk and replace the smallest one in the array and increase the volume without affecting current data on the volume/disks.
6. it should be possible to create backup of USB drive with OS, so if it fails, backup one can replace it and NAS continue to run.
7. it should be possible to copy my data over network from old NAS to OMV and verify that it has been copied without errors. It would be nice if it can be done through GUI instead of CLI
8. it should be possible to backup certain folders (not necessarily the whole volume) on external disk via USB.
9. it should be possible to plug such external USB disk into Windows machine and read data if necessary.
Before I completely move my data on new OMV NAS, I plan to run tests and simulate most of the failure scenarios and post my findings here.
Nice to have features:
1. ability to create two volumes, one with redundant data (containing family photos and other data that cannot be obtained from elswhere), and one with non-redundant data, which are not so important (e.g. ripped DVDs, which can be ripped again or bought again if disks fail)
2. ability to run Logitech's squeezebox server (Old Netgear's NAS has such plugin and that was one of the reasons I bought it. Synology's NASes have it as well)
3. ability to do backups of certain data via internet on other OMV machine
As I go further into this project, the new questions might appear so I might open additional topics to keep this post clean and post links to them.
Also, new features might come to my mind, so I might extend the lists above.
Just to get feeling of OMV, I installed it on USB stick (v 3.x with omv-extras plugin and flashmemory plugin), with no data disks being inserted yet and I like it so far 
.
So can someone experienced comment on my essential features and confirm that they are achievable with OMV, please?