External hard drive not showing up in RAID

  • Hi,


    I am setting up my nas for the first time. I am using 3x500gb internal hard drive and 2x500gb external hard drive (connected via usb) however these drives are not showing up when I try to put them into RAID, I believe this is because the devices are connected via usb however I do not know what to do as I would like to have the extra 1 TB of space. Please let me know if I need a plugin or what I can do. As you can see from the images the drives are showing up Screenshot 2019-05-08 at 23.24.36.png but are not actually allowing me to put them in RAIDScreenshot 2019-05-08 at 23.24.44.png


    Thank you

  • So just to clarify there is no way I can use external hard drives in a raid array.

    There is no way to create an array from the web interface using usb drives.


    Can I ask why? (I know you said it was a very bad idea but could you clarify)

    Raid is intended to provide redundancy (not backup). Other than the fact that most home users don't need redundancy, usb drives are not cooled well, have a unreliable interface (usb), typically use cheap drives, have no way to provide redundant power, and are usually set to go to sleep after a short amount of inactivity. Most raid configurations will write to the drives more due to parity and/or mirroring. The drives will be put under a lot of stress generating a lot of heat when syncing. raid doesn't do well with usb drives that start slow at boot and will cause the array fail to assemble. raid doesn't do well with drives that go to sleep. Faster drives in the array can only read or write as fast as the slowest drive. Is that enough reasons?

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  • Raid is intended to provide redundancy (not backup). Other than the fact that most home users don't need redundancy, usb drives are not cooled well, have a unreliable interface (usb), typically use cheap drives, have no way to provide redundant power, and are usually set to go to sleep after a short amount of inactivity. Most raid configurations will write to the drives more due to parity and/or mirroring. The drives will be put under a lot of stress generating a lot of heat when syncing. raid doesn't do well with usb drives that start slow at boot and will cause the array fail to assemble. raid doesn't do well with drives that go to sleep. Faster drives in the array can only read or write as fast as the slowest drive. Is that enough reasons?

    Thanks that is enough reasons I was just interested as I am new to all of this.


    My other question then is can I attach the usb storage drives to the nas and have them go through network (without raid or anything else) but still going through openmediavault and the nas if that makes sense.

  • My other question then is can I attach the usb storage drives to the nas and have them go through network (without raid or anything else) but still going through openmediavault and the nas if that makes sense.

    Yes, you can attach usb drives, format them, and then share them.

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  • OMV does not allow you to use usb drives in a raid array because it is a very bad idea.

    Does this mean if I get a raspberry pi 3 Model B+ I am not able to put the drives in RAID because the only way I can think of connecting the drives to a raspberry pi is by usb and you have said I am not able to do this. So I am wondering gif you know another way to connect the drives in RAID or another way of connecting the drives to the raspberry pi

  • Does this mean if I get a raspberry pi 3 Model B+ I am not able to put the drives in RAID because the only way I can think of connecting the drives to a raspberry pi is by usb and you have said I am not able to do this. So I am wondering gif you know another way to connect the drives in RAID or another way of connecting the drives to the raspberry pi

    Obviously, usb is the only way to connect a drive to an RPi. Why do you insist on buying an RPi? And after all of my comments, why would you still insist on using usb drives in a raid array?

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  • There is no way to create an array from the web interface using usb drives.

    Raid is intended to provide redundancy (not backup). Other than the fact that most home users don't need redundancy, usb drives are not cooled well, have a unreliable interface (usb), typically use cheap drives, have no way to provide redundant power, and are usually set to go to sleep after a short amount of inactivity. Most raid configurations will write to the drives more due to parity and/or mirroring. The drives will be put under a lot of stress generating a lot of heat when syncing. raid doesn't do well with usb drives that start slow at boot and will cause the array fail to assemble. raid doesn't do well with drives that go to sleep. Faster drives in the array can only read or write as fast as the slowest drive. Is that enough reasons?

    I see your point in USB drives up to a point - I have a multi-drive, USB 3.1 enclosure with fan and 6TB archival drives. I should be able to use them in a RAID if I desire. Even if I had a 4-card USB setup and 4 individual drives hanging off of them, it would be better to have RAID than to have no redundancy. If someone doesn't do their due diligence and configures a USB environment that cannot handle the stresses, it should be on them and not by preventing ALL users from doing it.

  • it should be on them and not by preventing ALL users from doing it.

    ?( no one is preventing anyone from creating a Raid using USB, but the function to create the Raid from within OMV's GUI is disabled. A user can create a Raid using the command line, if a user wishes to create a Raid on a Raspberry Pi which this thread is about, my response is, if it goes wrong don't call us we'll call you :)

  • For some (most? all?) home users, experimenting with RPi, having RAID is worse than not having RAID. The reason is that they seem to think that their data will continue to be available in case one drive fail. Also they seem to think RAID means they can ignore backups. Using an extra drive for redundancy means a greater risk for errors. Not less. Also RAID on RPi typically means a USB hub, lots of cables and connectors. Lots of things that may go wrong and even may blow the RPi itself.

    Be smart - be lazy. Clone your rootfs. This help is Grateful™.
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  • it would be better to have RAID than to have no redundancy

    Your raid array would be the only thing that would be redundant and even it really isn't redundant since I highly doubt your external enclosure has multiple usb links in case one goes down or multiple power supplies in case one fails. If you are using a system without raid, your backups are your redundancy. And you can always use snapraid with mergerfs for pooling.

    omv 5.5.0 usul | 64 bit | 5.4 proxmox kernel | omvextrasorg 5.3.3
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