A RAID-less plan?

  • I saw the "thoughts on RAID" thread and apparently can't comment there. But I resonated with the perspectives presented there and have questions.


    I'm an independent software dev and have had RAID 1 running on my main workstation for years (windows 7, intel software raid). I've wanted RAID because if a disk dies I have a working machine and just need to rebuilt the array with a new participant disk. It has been a good premis.


    OTOH I have found that with my very intermittent 'hands on' with RAID config, it can be dicey whenever I do need to deal with RAID issues. From this angle, RAID introduces risk. Also, if my machine crashes (bsod kind of things) the RAID array rebuild time is hard to live through (two 1.5 TB disks), as it consumes a lot of RAM and cpu cycles.


    I've started to think I'll go RAID-less on my next workstation. SSD (which I have never touched to date) are getting big enough and are apparently less likely to fail than spindle drives. I have not figured out whether it'd be safe enough to trust the SSD to the degree that I could drop raid, but I hope I can work it out. Backups have to be regular and tested, of course.


    I'm a new OMV user and today I started the machine up for the first time in almost a week. I had created a RAID 10 array (4 - 4 TB disks) thinking speed and resilience, and that a NAS would have few crashes and that rebuilts would be rare. But I see that for some reason my array is resyncing...I guess that means rebuilding the array. This and the 'thoughts about raid' thread and my own cautions about RAID have me wondering if I ought to forgo RAID on the NAS and take another route to ensure durability of the data stored on the NAS.


    If I don't use RAID on the NAS and a disk fails and that's my only copy of the data then I'd be bummed. The OMV non-RAIDers out there must have the same concerns. So what do you do? You have two NAS units?

  • While I understand that thread, I don't always agree with it. I have been using mdadm software raid arrays for lots of years. I currently have machines with three raid 5, two raid 10, and one raid 0 array. And yes, I backup to a second NAS.


    Do I think raid is good for everything or everyone? No. Is running without raid a risk? Not if you have backup. For people that are new to Linux, I would stick with solutions like snapraid if you even need redundancy. Everyone should have backup no matter what their solution is.

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  • Yeah, I think the two posters in the other thread and you and I agree that RAID has it's place. I have work servers that run on raid arrays and it'd be crazy not to do that.


    I'm sure you're far more experienced than I am with RAID. I had never even heard of snapraid until now - it's not something on uses with OMV, correct? It's more like something one might use on a linux workstation or server?


    "Everyone should have a backup" we all agree on that also. The thing is, with my OMV NAS I was planning on having my backups stored on a RAID array...so the backup is dependent on my management of the raid array.


    I am probably in a middle ground where I am familiar with the various risks and solutions to some degree, but not really wise in these areas. What I'd worry about with a RAID-less NAS is any data that exists in that one location is lost. If I have two NAS both non-raid then I could have a backup of the backup. I'm not sure what is best.


    BTW you said 'is running without raid a risk' ' not if you have backup' but I don't think that can be exactly true. You'd be good as far as your most recent backup goes. That's what I have counted on from RAID - a single disk going south does not mean a loss of a days work.


    I am interested in hearing whatever else anyone has to say on this. This was my first RAID 10 experience; I was very surprised to see it rebuilding already...I don't get that.

  • There is a snapraid plugin for OMV.


    As for the most recent backup issue... I have rsnapshot jobs that run many times a day for documents. This backs up multiple copies of documents to a different drive on the same server. Once a day, this backup is rsync'd to another NAS. The chances of losing recent documents is very small.


    I love raid 10. I have never had an issue with it. Is it rebuilding or just running its monthly check?

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  • Thanks again for that input. Since I'm new to all of this (nas, omv) it may be a bit much for me to venture into snapraid. Why do you choose it over the raid that is built in to OMV? Or is it more of a complimentary management enhancement to the OMV RAID, and not a replacement? I also have not heard of rsnapshot, but it seems it's linux etc not windows and windows is where my work takes place. I may be able to find something parallel in the windows world.


    It just says resyncing (81% right now). I have no idea why...OMV has been installed for a week, and the NAS was off for 4 days straight.

  • snapraid works on top of the filesystems. So, nothing to risk. It just calculates parity and writes that data to one drive. Very similar to raid5 but not in realtime. You have to tell it when to calculate. You most likely would not use it with real raid.


    rsnapshot is a plugin as well. It runs on the server to make multiple hourly, daily, weekly, monthly, and yearly backups. It saves space by linking to the existing copies if they have not changed.


    Your array might be doing the monthly check. Hard to tell.

    omv 5.3.9 usul | 64 bit | 5.3 proxmox kernel | omvextrasorg 5.2.6
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  • I am anti raid more due the reliability of the higher capacity disks. Since we have moved above the 1 tb level they do not seem as reliable. I think that is evident in the forums by the numerous people that have issues. I used to see many drives on newegg that had a 95 positve rating, just accounting for the 4 and 5 egg ratings. Now you are lucky to see 70-80 percent positive. There are excpetions but still unnerving.


    If I did not have continuous backup I would use SnapRaid. I think it is worth the investment in time for the redundancy. It is however not a true backup.

  • And tekkb, what are you using for continuous backup? And in the other thread you say "I have a 2nd server and make backups of each data drive", can you be more explicit? Your server #1 is in use not as a backup device but as a production server of some sort; and you back it up to a second server? And the #2 is an OMV NAS?


    I'm trying to get a sense of what others that have been around longer than I in the NAS space are doing.


    The time to rebuild large capacity hdd and the seemingly increasing rate of failure is also why I'm going a bit cold on raid...but warming up to multiple, independent backup locations.

  • ryecoaaron, when you wrote


    "rsnapshot is a plugin as well. It runs on the server to make multiple hourly, daily, weekly, monthly, and yearly backups. It saves space by linking to the existing copies if they have not changed"


    Is the 'server' the OMV NAS? Or a regular linux etc server (not just a storage device). I think you mean a regular server...and from what little I've read, rsnapshot copies files etc in almost realtime. Maybe that's what tekkb is using for his continuous backup?

  • I use a pay service, CrashPlan. There is a backup set for each individual data drive on Server 1. One of the drives on Server 1 has a backup shared folder where I backup all my machines in my LAN. For my windows machines I use Acronis.


    Server 2 is purely a backup machine. It's job is to basically keep my data safe.


    Both run OMV. Continuos backup and versioning is nice... but a lot of people here are not interested in pay services.

  • Hi Mikado!


    I wrote the other thread. It's about my opinion and so I don't wanted a discussion in general about it. And as you see - it works: You set up a new thread and you're going deeper into things. :)


    My lines have been primary addressed to homeusers. So I pointed out, that RAID can be helpful if you're running a business - like you do.


    I understand and accept Aaron's point of view. He's a pro, he's knowing what to do, when the RAID is struggling with problems. He's not a normal homeuser. ;-)


    OTOH I have found that with my very intermittent 'hands on' with RAID config, it can be dicey whenever I do need to deal with RAID issues. From this angle, RAID introduces risk. Also, if my machine crashes (bsod kind of things) the RAID array rebuild time is hard to live through (two 1.5 TB disks), as it consumes a lot of RAM and cpu cycles.


    Yes - that's one point. If you RAID in your workstation is RAID 1 with two HDD's, only one could fail. You've missed that point, that a rebuild is stressing the remaining HDD. When your workstation was build, both HDDs are same age, have same powercycles and so on. Let's face it: Chances are, that your remaining HDD is getting trouble via rebuild.


    You're OMV is running RAID10 (8 TB data, fault tolerance 1-drive failure). Your box is new. So you got around 4 TB data. First thing I would ask, if all this data is daily used. If most data is just archived, I would swap to another solution.


    If I don't use RAID on the NAS and a disk fails and that's my only copy of the data then I'd be bummed. The OMV non-RAIDers out there must have the same concerns. So what do you do? You have two NAS units?


    Backups will be covert in the next "My thoughts about". So in short: I've got two OMVs (see below).


    First one is an archive, so it's kind of cold storage. It's not powered on, it's not connected with the powerplug or router. It's just get connected, when really needed. It has 4 HDDs: 1 - personal data, 2 - private images (> 70000), personal videos, 3 - internal Backup to 1, 4 - internal Backup to 2. So I do internal mirroring - every five hours when running or manual. The backup-HDDs are read-only from client-side. Then I've real cold storage: encrypted HDDs. On in my cupboard, the other one some kilometers away in my working-place. When I want to update my encrypted HDDs, I go to my cupboard, grab that HDD, mirror the data and on the next working-day I'll swap the HDD in my working-desk. Arrived at home I update this HDD and store it in my cupboard. So I've three backups, two offside.


    The second NAS is only for multimedia. It stores movies and tv-shows, that I've recorded via PVR from TV. This is one HDD at this time and it is not important to me. There are so many recurrences in TV, that I do not need a backup. ;) The reason for the recordings is, that I want to decide, when I want to see a movie.

  • It is backed up on my drives on the 2nd server and in the cloud. I am comfortable with the encryption employed by CP. I understand people not trusting and everyone is free to make their own choice. But is it not helpful to always share information. It at least helps people to make a more informed decision.


    I think your recent posts with your ideas are good. But why close them. Let others discuss your ideas. You should not feel obligated to post further after your opening post.


    We made this your home too. And we respect you. If you want to make blog like posts we let you do it.

  • ryecoaaron, when you wrote


    "rsnapshot is a plugin as well. It runs on the server to make multiple hourly, daily, weekly, monthly, and yearly backups. It saves space by linking to the existing copies if they have not changed"


    Is the 'server' the OMV NAS? Or a regular linux etc server (not just a storage device). I think you mean a regular server...and from what little I've read, rsnapshot copies files etc in almost realtime. Maybe that's what tekkb is using for his continuous backup?


    As I said, rsnapshot is a plugin for OMV. rsnapshot runs when it is scheduled not in realtime.

    omv 5.3.9 usul | 64 bit | 5.3 proxmox kernel | omvextrasorg 5.2.6
    omv-extras.org plugins source code and issue tracker - github


    Please read this before posting a question.
    Please don't PM for support... Too many PMs!

  • Your inputs in this thread, and the original thread about RAID, have been very helpful to me.


    I have been using backblaze for years; it's very similar to crashplan. I know it does not back up changed files immediately; it is possible that crashplan is closer to real time backup, but I'm not certain.

  • I'm running into this dilemma myself right now.


    Most of what is on the current nas I'm building will be stuff like TV and Movies. These are things I really don't need a backup of, they can be easily re-ripped/downloaded. However, losing a single drive would be a pretty serious pain comparatively. So it seems to me, either using mdadm raid 5, or jbod and snapraid would make the most sense.


    What are your thoughts on those kinds of storage requirements?

  • I have pretty much the same situation. Currently I´m having RAID 5 but in the future I´ll use just single drives - even without pooling, because I do not have such important media... And one or two external drives which I will use for an RSYNC backup from the main big drives. Thats it.

    OMV 4.x| HP Microserver | 256GB Samsung 830 SSD for system | 4x 2TB in a RAID5
    OMV 4.x| Odroid XU4 | 5TB Data drive | 500GB Backup drive
    OMV 5.x| Raspberry Pi 4 | 6TB Data drive | 500GB SSD drive

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