It changes your redundancy calculations slightly. For instance, you could configure 8 disks as a single raidz2 vdev or two 4 disk raidz1 vdevs. Both setups could have a maximum of 2 disks fail, but with the raidz2 setup you could have any 2 disks fail, while in the raidz1 setup the failed disks would need to be in separate vdevs. In some scenarios you can only have a single disk fail before losing the pool. What you gain by having more vdevs is performance, because you stripe I/O between all vdevs. The two 4 disk raidz1 vdev setup mentioned above would have roughly twice the performance of a single raidz2 with the same 8 disks. The dual raidz1 setup would also be quicker to rebuild, because you only need to resilver 4 disks instead of 8 when replacing a failed drive.
Hi, Great tip labeling the disks. I’m having an issue now using proxmox with two Sata doms mirrored for the OS. There internal no way to label. One is bad and I can’t figure out how to tell which one it is. Any thoughts?
Ugh…that's quite a problem. Unfortunately I don't have anything to suggest. If your motherboard or manual has the slots labeled, I would guess the lowest /dev id might match with the first slot on the MB? But that's not always the case. Hope you were able to get this resolved!
Great tip labeling the disk. I’m having an issue now I have two sata doms mirrored in OS and I can’t figure out which one is bad. No way to label being internal. Any thoughts?
That's a tough one. :-) You might just need to shutdown the server to find out. Do the internal SATA DOMs have any serial numbers printed on them? If not, you could always mirror a third disk for the boot volume and then guess. All else being equal, I'd think ada0 would be the first SATA DOM slot, and ada1 being the second, if there are markings on the motherboard. Make sure before trying anything to download a backup configuration file from TrueNAS. That way if something goes wrong while trying to replace the bad SATA DOM, you can always just start fresh and re-import the configuration. The storage pool(s) should be left untouched in that situation (but you should always have a backup of that too).
I hVe 3 different sized hard drives. My question is on TrusNas what is the easiest way to maximize my space on them? Mirroring will eat a lot of space and striping is not recommended. Should I just make 3 different pools or?
Ben's got it there… I'd recommend same size-vdevs in a pool (and same-size disks in a vdev). The other advantage of going with 3 different pools is if you have a disk failure, your other 2 pools are still accessible.
Thanks guys. I bouch an old school matx chassis last year for my NAS. I decided to populate the 2 5.25 bays w a 3 bay hot swap drive. Hence why I asked about it. Thinking about adding an extra ssd for caching.
@@TheBobcat1978 Having an SSD for L2ARC can help in certain situations, but you're better off adding more RAM first if the server will support it. With 48GB of RAM on my NAS, I consistently see cache hit rates above 90% (almost always in the high-90s). If you do go the SSD route for a cache, make sure you get a drive with a high write endurance. I've had cache SSDs in my Synology die in less than a year due to running beyond the rated TBW.
Hey I have dought. I am planning to make a nas with truenas. I want 4tb storage from my two 2 tb hard disk which raid must I use ? I don't want mirror. because it gives me half the storage if I mirror it. I only use these hard disk to save my old pics and family videos. I am willing to risk it.
If you have 2 disks, the only redundant option is to mirror. If you don't want to mirror, then I would set them up as two separate volumes. That way, if one disk fails, you only lose half of your data. Make sure you have a backup though, even if you mirror. I'd be crushed if I lost my old pictures and family videos.
If you have 2, 2tb, then YOU should get 2 more 2TB drives and have them on zfs Raidz2 You will have total 4tb and 2 drives redundancy so you dont loss anything when 2 drives fails
