New To OpenMediaVault

    • New To OpenMediaVault

      Hi All i hope this is the correct place to ask.
      Sorry for the noob questions but i am new here and i need some help.

      I am coming from a product called Flexraid but the developer have not been seen in about 8 Months.

      So here is goes .

      How do i recover Data if i have a drive that fails.
      i see a lot of people saying snap raid is the way to go but very confused on how it works.

      I have a lot of stuff on my 10 TB system that i would like to protect from hard-drive failures.

      Currently i am testing it and so far i am very impressed on how easy the systems works thanks to Techno Dad Life awesome Videos.

      If anyone can assist will be appreciated.
    • Before you do not write the name of the project correct, until then you'll get now answer :)

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    • Morne wrote:

      I have a lot of stuff on my 10 TB system that i would like to protect from hard-drive failures.
      That is what backups are for. Raid (flexraid, snapraid, etc) are for redundancy.

      votdev wrote:

      Before you do not write the name of the project correct, until then you'll get now answer
      I had to fix it... It was really bugging me.

      Morne wrote:

      How do i recover Data if i have a drive that fails.
      Search the forum for snapraid. There are a few threads about how this is done. Reading the snapraid manual and then looking at the plugin's options would be good too.
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    • Morne wrote:

      How do i recover Data if i have a drive that fails.
      SNAPRAID manual. Scroll down to 4.4 "Recovering"


      Morne wrote:

      I have a lot of stuff on my 10 TB system that i would like to protect from hard-drive failures.
      I agree with @ryecoaaron and many other experienced users and admin's; SNAPRAID is no substitute for backup or, to be specific, at least one full second copy of your data.

      At an absolute minimum, consider getting a big internal or external drive (10TB) and cloning your data store with Rsync.

      The post was edited 2 times, last by crashtest ().

    • Morne wrote:

      Looking at the guide now.
      Great!

      And if you want to pool drives together, consider using the UnionFS plugin (which is mergerfs). SNAPRAID+UnionFS will provide an array that's similar to RAID 5, but with superior capabilities for protecting and recovering data. I'd really like to see the SNAPRAID+UnionFS combo catch on. It's one of the safer ways to deal with a collection of drives, that's also friendly to USB.

      If you're interested, there are a number of mergerfs threads on the forum.
    • The video will get you started. I've been giving some thought to writing up a guide to provide an overview of what SNAPRAID is, the basics of how it works, and the automation of maintenance tasks. In addition, mergerfs has a few considerations that would be worth knowing before setting it up.

      For instance, video storage is the 400lb gorilla in the room:
      A video data store has the potential to be massive. If the NAS is intended for a large collection of video files, the default policy "Existing Path, Most Free Space" should be changed to "Most Free Space". The Most Free Space policy will distribute files evenly among all drives, maintaining equal free space among member drives.
      On the other hand, if storage is mostly Video, the default policy "Existing Path, Most Free Space" will likely fill one drive to capacity. (The first directive "Existing Path", will direct files to where the shared folder "Videos" exists.)

      The down side to the "Most Free Space" policy is, with even distribution of files among all drives in an overlayfs fashion, you're more committed to using mergerfs.
      If there's a balance between Video and all other files, "Existing Path, Most Free Space" makes sense because files are consolidated according to data types set forth by the user when shared folders are set up. (Video, Documents, Pictures, etc.) The "Existing Path, Most Free Space" policy makes it easier to deal with problems, move data, or even back out of mergerfs altogether.

      The post was edited 1 time, last by crashtest: edit ().

    • crashtest wrote:

      writing up a guide to provide an overview of what SNAPRAID is, the basics of how it works, and the automation of maintenance tasks.
      I would really like that!

      Moreover UnionFS gave me some headaches and I eventually ditched it.
      (Although my first testings where positive! But somehow a few weeks and a few OMV installs later I couldn't make it work again.)

      So I would be really interested in the combination of UnionFS and SnapRAID.
    • wolf8auer wrote:

      So I would be really interested in the combination of UnionFS and SnapRAID.
      The combination, when setup with a just a few details observed for the use case, is outstanding. It's superior to RAID5. In fact the only feature RAID5 has over a SNAPRAID+UnionFS is higher (parallel) read and write throughput. Higher I/O may be good in a production environment, but it's not really necessary for a small LAN server. Also, it's RAID5's parallel reads and writes that cause problems with USB connected drives which are, by definition, "serial" connections. USB can't provide equal bandwidth to all drives. With SNAPRAID+UnionFS, this is not a problem.

      One of SNAPRAID's features that I appreciate the most is data integrity and preservation or, as it's commonly referred to, "bit-rot" protection. CoW filesystems provide bit-rot protection, but ZFS and BTRFS require some form of a RAID1 equivalent to implement it. (There's a way to achieve it in ZFS, with a filesystem setting of Copies=2, but that's a side note.)
      In any case, true bit-rot protection comes from duplicate files with checksums. A "scrub" checks files against their checksums and overwrites a bad file (one that doesn't match it's checksum) with the good second copy (the file that does match it's check sum). Otherwise, without the second file, all that could be done would be to report an unrepairable error.

      Two files means, 2X the disk space is required for data intergrity, hence the RAID1 or mirror equivalent. If 2TB is to be protected, it takes 4TB of disk space. SNAPRAID, on the other hand, does the same job using a content file and 1 parity disk to (safely) protect up to 3 data disks. Instead of a 50% loss of space, it's 33% to protect 2 data disks, or 25% to protect 3. So, for bit-rot, it's more space efficient.
      ________________________________

      These topics are not really complicated, but writing them up in a way that makes them seem simple can be. :)

      The post was edited 1 time, last by crashtest ().

    • wolf8auer wrote:

      I can't wait to get my new SBC and start to play with UnionFS again!
      Well, I have to caveat what I've said here. While my experiences have been very good, they are anecdotal and apply to just a few sets of hardware. Full backup is always a good idea - I'd go so far as to say "crucial". With backup, users are free to try new storage methods and advanced file systems without the need to worry.