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Cake day: November 5th, 2023

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  • I am assuming this is the LVM volume that Ubuntu creates if you selected the LVM option when installing.

    Think of LVM like a more simple more flexible version of RAID0. It isn’t there to offer redundancy but it take make multiple disks aggregate their storage/performance into a single block device. It doesn’t have all of the performance benefits of RAID0, particularly with sequential reads, but in the cases of fileservers with multiple active users it can probably perform even better than a RAID0 volume would.

    The first thing to do would be to look at what volume groups you have. A volume group is one or more drives that creates a pool of storage that we can allocate space from to create logical volumes. Run vgdisplay and you will get a summary of all of the volume groups. If you see a lot of storage available in the ‘Free PE/Size’ (PE means physical extents) line that means that you have storage in the pool that hasn’t been allocated to a logical volume yet.

    If you have a set of OS disks an a separate set of storage disks it is probably a good idea to create a separate volume group for your storage disks instead of combining them with the OS disks. This keeps the OS and your storage separate so that it is easier to do things like rebuilding the OS, or migrating to new hardware. If you have enough storage to keep your data volumes separate you should consider ZFS or btrfs for those volumes instead of LVM. ZFS/btrfs have a lot of extra features that can protect your data.

    If you don’t have free space then you might be missing additional drives that you want to have added to the pool. You can list all of the physical volume which have been formatted to be used with LVM by running the pvs command. The pvs command show you each formatted drive and if they are associated with a volume group. If you have additional drives that you want to add to your volume group you can run pvcreate /dev/yourvolume to format them.

    Once the new drives have been formatted they need to be added to the volume group. Run vgextend volumegroupname /dev/yourvolume to add the new physical device to your volume group. You should re-run vgdisplay afterwards and verify the new physical extents have been added.

    If you are looking to have redundancy in this storage you would usually build an mdam array and then do the pvcreate on the volume created my mdadm. LVM is usually not used to give you redundancy, other tools are better for that. Typically LVM is used for pooling storage, snapshots, multiple volumes from a large device, etc.

    So one way or another your additional space should be in the volume group now, however that doesn’t make it usable by the OS yet. On top of the volume group we create logical volumes. These are virtual block devices made up of physical extents on the physical disks. If you run lvdisplay you will see a list of logical volumes that were created by the Ubuntu installer which is probably only one by default.

    You can create new logical volumes with the lvcreate command or extend the volume that is already there. Or resize the volume that you already have with lvresize. I see other posts already explained those commands in more detail.

    Once you have extended the logical volume (the virtual block device) you have to extend the filesystem on top of it. That procedure depends on what filesystem you are using on your logical volume. Likely resize2fs for ext4 by default in Ubuntu, or xfs_growfs if you are on XFS.



  • Good catch on the redundancy, at the time posting this I didn’t realize I needed the physical space/drives to set up that safety net. 8 should be plenty for the time being. Say if I wanted to add another drive or two down the road, what sort of complications would that introduce here?

    With TrueNAS your underlying filesystem is ZFS. When you add drives to a pool you can add them:

    • individually (RAID0 - no redundancy, bad idea)
    • in a mirror (RAID1 - usually two drives, a single drive failure is fine)
    • raidz1 (RAID5 - any single drive in the set can fail, one drive’s worth of data does to parity). Generally a max of about 5 drives in a raidz1, if you make the stripe too wide when a drive fails and you start a rebuild to replace it the chances of one of the remaining drives you are reading from failing or at least failing to read some data increases quickly.
    • raidz2 (RAID6 - any two drives can fail, two drives worth of data goes to parity). I’ve run raidz2 vdev up to about 12 drives with no problems. The extra parity drive means the chances of data corruption, or of a other drive failing while you are rebuilding is much lower.
    • raidz3 (triple parity - any three drives can fail, three drives worth of data goes to parity). I’ve run raidz3 with 24 drive wide stripes without issues. Though this was usually for backup purposes.
    • draid (any parity level and stripe switch you want). This is generally for really large arrays like 60+ disks in a pool.

    Each of these sets is called a vdev. Each pool can have multiple vdevs and there is essentially a RAID0 across all of the vdevs in the pool. ZFS tends to scale performance per vdev so if you want it to be really fast, more smaller vdevs is better than fewer larger vdevs.

    If you created a mirror vdev with two drives, you could add a second mirror vdev later. Vdevs can be of diferent sizes so it is okay if the second pair of drives is a different size. So if you buy two 10TB drives later they can be added to your original pool for 18TB usable.

    What you can’t do is change a vdev from one type to another. So if you start with a mirror you can’t change to a raidz1 later.

    You can mix different vdev types in a pool though. So you could have two drives in a mirror today, and add an additional 5 drives in a raidz1 later.

    Drives in a vdev can be different sizes but the vdev gets sized based on the smallest drive. Any drives that are larger will be wasting space until you replace that smaller drive with a similar sized one.

    A rather recent feature lets you expand raidz1/2/3 vdevs. So you could start with two drives today in a raidz1 (8TB usable), and add additional 8TB or higher drives later adding 8TB of usable space each time.

    If you have a bunch of mismatched drives of different sizes you might want to look at UnRAID. It isn’t free but it is reasonably priced. Performance isn’t nearly as good but it has its own parity system that allows for mixing drives of many sizes and only your single largest drive needs to be used for parity. It also has options to add additional parity drives later so you can start at RAID5 and move to RAID6 or higher later when you get enough drives to warrant the extra parity.


  • My server itself is a little HP mini PC. i7, 2 TB SSD, solid little machine so far. Running Proxmox with a single debian VM which houses all my docker containers - I know I’m not using proxmox to its full advantage, but whatever it works for me. I mostly just use it for its backup system.

    Not sure how mini you mean but if it has spots for your two drives this should be plenty of hardware for both NAS and your VMs. TrueNAS can run VMs as well, but it might be a pain migrating from Proxmox.

    Think of Proxmox as a VM host that can do some NAS functions, and TrueNAS as a NAS that can do some VM functions. Play with them both, they will have their own strengths and weaknesses.

    I’ve been reading about external drive shucking, since apparently that’s a thing? Seems like my best bet here would be to crack both of these external drives open and slap them into a NAS. 16TB would be plenty for my use.

    It’s been a couple of years since I have shucked drives but occasionally the drives are slightly different than normal internal drives. There were some western digital drives that had one pin that was different from normal and worked in most computers, but some power supplies which had that pin wired required you to mask the pin before the drive would fire up.

    I wouldn’t expect any major issues just saying you should research your particular model.

    You say 16TB with two 8TB drives so I assume you aren’t expecting any redundancy here? Make sure you have some sort of backup plan because those drives will fail eventually, it’s just a matter of time.

    You can build those as some sort of RAID0 to get you 16TB or you can just keep them as separate drives. Putting them in a RAID0 gives you some read and write performance boost, but in the event of a single drive failure you lose everything.

    If 8TB is enough you want to put them in a mirror which give you 8TB of storage and allows a drive to fail without losing any data. There is still a read performance boost but maybe a slight loss on write performance.

    Hardware: while I like the form factor of Synology/Terramaster/etc, seems like the better choice would be to just slap together my own mini-ITX build and throw TrueNAS on it. Easy enough, but what sort of specs should I look for? Since I already have 2 drives to slap in, I’d be looking to spend no more than $200. Alternatively, if I did want the convenience and form factor of a “traditional” NAS, is that reasonable within the budget? From what I’ve seen it’s mostly older models in that price range.

    If you are planning on running Plex/Jellyfin an Intel with UHD 600 series or newer integrated graphics is the simplest and cheapest option. The UHD 600 series iGPU was the first Intel generation that has hardware decode for h265 so if you need to transcode Plex/Jellyfin will be able to read almost any source content and reencode it to h264 to stream. It won’t handle everything (i.e. AV1) but at that price range that is the best option.

    I assume I can essentially just mount the NAS like an external drive on both the server and my desktop, is that how it works? For example, Jellyfin on my server is pointed to /mnt/external, could I just mount a NAS to that same directory instead of the USB drive and not have to change a thing on the configuration side?

    Correct. Usually a NAS offers a couple of protocols. For Linux NFS is the typical filesystem used for that. For Windows it would be a Samba share. NFS isn’t the easiest to secure, so you will either end up with some IP ACLs or just allowing access to any machine on your internal network.

    If you are keeping Proxmox in the mix you can also mount your NFS share as storage for Proxmox to create the virtual hard drives on. There are occasionally reasons to do this like if you want your NAS to be making snapshots of the VMs, or for security reasons, but generally adding the extra layers is going to cut down performance so mounting inside of the VM is better.

    Will adding a NAS into the mix introduce any buffering/latency issues with Jellyfin and Navidrome?

    Streaming apps will be reading ahead and so you shouldn’t notice any changes here. Library scans might take longer just because of the extra network latency and NAS filesystem layers, but that shouldn’t have any real effect on the end user experience.

    What about emulation? I’m going to set up RomM pretty soon along with the web interface for older games, easy enough. But is streaming roms over a NAS even an option I should consider for anything past the Gamecube era?

    Anything past GameCube era is probably large ISO files. Any game from a disk is going to be designed to load data from disk with loading screens, and an 8tb drive/1gb Ethernet is faster than most disks are going to be read. PS4 for example only reads disks at 24MB/s. Nintendo Switch cards aren’t exactly fast either so I don’t think they should be a concern.

    It wouldn’t be enough for current gen consoles that expect NVMe storage, but it should be plenty fast for running roms right from your NAS.