Looking to be building a new NAS to be replacing dying Synology Rackstation.
Been wanting to do TrueNAS for awhile but Syno has always been ‘good enough’ but my hand is being forced to build anew and the warranty has expired right before I could even make use of it.
Currently have 4x14TB in RAID10, BTRFS volume, 2x512GB nvme SSDs for caching + metadata cache on that synology rig.
Looking to build a 4x24TB TrueNAS system, just trying to figure out what is optimal. I’m expecting to have 128GB of ECC in here, or potentially more if it makes sense. Is there a guide or calculator for how much RAM should be available depending on the volume size? Is the 1GB ram per 1TB of space still the rule of thumb for calculating ARC?
This will mostly be storing media files, pictures, documents, but will also be used for VM backups, potentially some secondary VM storage, and some other both large and small file transfers between servers / temporary storage.
SLOG, L2ARC, and Metadata vdev all sound of interest but I see so much conflicting discussion, but it’s also tempered by the fact that lots of topics that come up on searches are anywhere between 2012-2020 in age, and surely there have been changes/improvements to ZFS and hardware in that period of time. If there’s any sort of guide or calculator on how big SLOG/L2ARC/metadata should be, that would be helpful.
I see routinely they say that SLOG doesn’t need to be very big? <32GB in size? Or that it should be speed of writing to volume (MB/s) * 5-10s?
I haven’t decided where I could make use of my two existing nvme SSDs (they’re 970 Pros) yet. Haven’t decided what to do for bootdrive yet either. I’m also considering purchasing some Intel Optane drives too, if they’d make more sense than the 970s for either Boot drive / SLOG / L2ARC / or Metadata vdev purposes.
The other big question would be layout/config of ZFS on 4x24TB themselves. I’m currently looking to recreate a RAID10-like setup in ZFS, web suggests that “create two 2-disk mirror vdevs, which ZFS will then stripe across” would be equiv / good? How would this compare to RAID-Z2? (Both in usable space, as well as read speed, write speed, as well as potential for how many drives could be lost. Is it still up to 2 drive loss for both? And only 1 drive potentially depending which fails for the faux Raid10 setup? Thanks all