dotfiles/config/nixos/hardware/mennos-server/zfs.nix

{ config, pkgs, ... }:
{
  # Enable ZFS support
  boot.supportedFilesystems = [ "zfs" ];

  # ZFS system services
  services.zfs = {
    autoSnapshot = {
      enable = false; # TODO: Enable this when we're ready to do so
      frequent = 4; # Keep 4 15-minute snapshots
      hourly = 24; # Keep 24 hourly snapshots
      daily = 7; # Keep 7 daily snapshots
      weekly = 4; # Keep 4 weekly snapshots
      monthly = 12; # Keep 12 monthly snapshots
    };
    autoScrub = {
      enable = true;
      interval = "weekly";
    };
  };

  # Install ZFS utilities
  environment.systemPackages = with pkgs; [
    zfs
    zfstools
  ];

  # If you want to keep compression settings
  boot.kernelParams = [ "zfs.zfs_compressed_arc_enabled=1" ];

  # TODO: Enable this when we're ready to do so
  # environment.etc."local/bin/zfs-backup.sh" = {
  #   mode = "0755";
  #   text = ''
  #     #!/bin/bash
  #     set -euo pipefail

  #     DATE=$(date +%Y%m%d-%H%M)
  #     DATASETS="music astro photos stash isos ai audiobooks vms old_backups services"
  #     RETAIN_SNAPSHOTS=24
  #     BACKUP_POOL="backup"
  #     SOURCE_POOL="datapool"

  #     log() {
  #       echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*"
  #     }

  #     ensure_backup_pool() {
  #       if ! zpool list "$BACKUP_POOL" >/dev/null 2>&1; then
  #         log "ERROR: Backup pool '$BACKUP_POOL' does not exist!"
  #         return 1
  #       fi
  #     }

  #     check_dataset_exists() {
  #       local pool=$1
  #       local dataset=$2
  #       zfs list "$pool/$dataset" >/dev/null 2>&1
  #       return $?
  #     }

  #     create_backup_dataset() {
  #       local dataset=$1
  #       local source_pool="$SOURCE_POOL"
  #       local backup_pool="$BACKUP_POOL"

  #       # Get properties from source dataset
  #       local props=$(zfs get -H -o property,value all "$source_pool/$dataset" | \
  #                    grep -E '^(compression|recordsize|atime|relatime|xattr|acltype)' | \
  #                    awk '{printf "-o %s=%s ", $1, $2}')

  #       log "Creating backup dataset $backup_pool/$dataset with matching properties"
  #       # shellcheck disable=SC2086
  #       zfs create -p ${props} "$backup_pool/$dataset"

  #       # Set some backup-specific properties
  #       zfs set readonly=on "$backup_pool/$dataset"
  #       zfs set snapdir=visible "$backup_pool/$dataset"
  #       log "Successfully created backup dataset $backup_pool/$dataset"
  #     }

  #     get_latest_snapshot() {
  #       local pool=$1
  #       local dataset=$2
  #       local snapshot
  #       snapshot=$(zfs list -t snapshot -H -o name "$pool/$dataset" 2>/dev/null | grep backup- | tail -n1) || true
  #       echo "$snapshot"
  #     }

  #     # Ensure backup pool exists
  #     ensure_backup_pool

  #     for ds in $DATASETS; do
  #         log "Processing dataset $ds"

  #         # Check if source dataset exists
  #         if ! check_dataset_exists "$SOURCE_POOL" "$ds"; then
  #             log "Skipping $ds - source dataset $SOURCE_POOL/$ds does not exist"
  #             continue
  #         fi

  #         # Create backup dataset if it doesn't exist
  #         if ! check_dataset_exists "$BACKUP_POOL" "$ds"; then
  #             log "Backup dataset $BACKUP_POOL/$ds does not exist"
  #             create_backup_dataset "$ds"
  #         fi

  #         # Create new snapshot
  #         local snapshot_name="$SOURCE_POOL/$ds@backup-$DATE"
  #         log "Creating new snapshot $snapshot_name"
  #         zfs snapshot "$snapshot_name"

  #         LATEST_BACKUP=$(get_latest_snapshot "$BACKUP_POOL" "$ds")

  #         if [ -z "$LATEST_BACKUP" ]; then
  #             log "No existing backup found - performing full backup of $ds"
  #             zfs send "$snapshot_name" | zfs receive -F "$BACKUP_POOL/$ds"
  #         else
  #             LATEST_SOURCE=$(get_latest_snapshot "$SOURCE_POOL" "$ds" | grep -v "backup-$DATE" | tail -n1)
  #             if [ -n "$LATEST_SOURCE" ]; then
  #                 log "Performing incremental backup of $ds from $LATEST_SOURCE to backup-$DATE"
  #                 zfs send -i "$LATEST_SOURCE" "$snapshot_name" | zfs receive -F "$BACKUP_POOL/$ds"
  #             else
  #                 log "No suitable source snapshot found for incremental backup - performing full backup of $ds"
  #                 zfs send "$snapshot_name" | zfs receive -F "$BACKUP_POOL/$ds"
  #             fi
  #         fi

  #         log "Cleaning up old snapshots for $ds"

  #         # Cleanup source snapshots
  #         if snapshots=$(zfs list -t snapshot -H -o name "$SOURCE_POOL/$ds" | grep backup-); then
  #             echo "$snapshots" | head -n -$RETAIN_SNAPSHOTS | while read -r snap; do
  #                 log "Removing source snapshot: $snap"
  #                 zfs destroy "$snap"
  #             done
  #         fi

  #         # Cleanup backup snapshots
  #         if snapshots=$(zfs list -t snapshot -H -o name "$BACKUP_POOL/$ds" | grep backup-); then
  #             echo "$snapshots" | head -n -$RETAIN_SNAPSHOTS | while read -r snap; do
  #                 log "Removing backup snapshot: $snap"
  #                 zfs destroy "$snap"
  #             done
  #         fi
  #     done

  #     log "Backup completed successfully"
  #   '';
  # };

  # systemd.services.zfs-backup = {
  #   description = "ZFS Backup Service";
  #   requires = [ "zfs.target" ];
  #   after = [ "zfs.target" ];
  #   path = [ pkgs.zfs ];
  #   serviceConfig = {
  #     Type = "oneshot";
  #     ExecStart = "/etc/local/bin/zfs-backup.sh";
  #     User = "root";
  #   };
  # };

  # systemd.timers.zfs-backup = {
  #   description = "Run ZFS backup every 4 hours";
  #   wantedBy = [ "timers.target" ];
  #   timerConfig = {
  #     OnBootSec = "15min";
  #     OnUnitActiveSec = "4h";
  #     RandomizedDelaySec = "5min";
  #   };
  # };
}