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nixos/modules/zfs.nix
Simon Gardling 39df22a96d
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zfs: tweak settings
2026-05-15 17:38:41 -04:00

105 lines
2.4 KiB
Nix

{
config,
lib,
service_configs,
pkgs,
...
}:
let
# Total RAM in bytes (from /proc/meminfo: 65775836 KiB).
totalRamBytes = 65775836 * 1024;
# Hugepage reservations that the kernel carves out before ZFS can use them.
hugepages2mBytes = service_configs.hugepages_2m.total_pages * 2 * 1024 * 1024;
hugepages1gBytes = 3 * 1024 * 1024 * 1024; # 3x 1G pages for RandomX (xmrig.nix)
totalHugepageBytes = hugepages2mBytes + hugepages1gBytes;
# ARC max: 60% of RAM remaining after hugepages. Leaves headroom for
# application RSS (PostgreSQL, qBittorrent, Jellyfin, Grafana, etc.),
# kernel slabs, and page cache.
arcMaxBytes = (totalRamBytes - totalHugepageBytes) * 60 / 100;
in
{
boot.zfs.package = pkgs.zfs_2_4;
boot.initrd.kernelModules = [ "zfs" ];
boot.kernelParams = [
"zfs.zfs_txg_timeout=30"
"zfs.zfs_arc_max=${toString arcMaxBytes}"
];
boot.supportedFilesystems = [ "zfs" ];
boot.zfs.extraPools = [
service_configs.zpool_ssds
service_configs.zpool_hdds
];
services.sanoid = {
enable = true;
datasets."${service_configs.zpool_ssds}" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 5;
daily = 7;
monthly = 3;
yearly = 0;
};
datasets."${service_configs.zpool_ssds}/services/sql" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 12;
daily = 2;
monthly = 0;
yearly = 0;
};
datasets."${service_configs.zpool_ssds}/services/jellyfin/cache" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 0;
daily = 0;
monthly = 0;
yearly = 0;
};
datasets."${service_configs.zpool_ssds}/services/monero" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 0;
daily = 0;
monthly = 0;
yearly = 0;
};
datasets."${service_configs.zpool_ssds}/services/p2pool" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 0;
daily = 0;
monthly = 0;
yearly = 0;
};
datasets."${service_configs.zpool_hdds}" = {
recursive = true;
autoprune = true;
autosnap = true;
hourly = 0;
daily = 0;
monthly = 0;
yearly = 0;
};
};
services.zfs = {
autoScrub.enable = true;
trim.enable = true;
};
}