Add notes on zfs and moving /var/log for advanced and storage focused users

advanced/var_log_move.md

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+# Move ```/var/log```
+
+ You can disable logging to ram by setting `ENABLED=false´ in  `/etc/default/armbian-ramlog´. 
+
+``` bash
+
+systemctl stop rsyslog.service
+systemctl stop syslog.socket
+lsof /var/log # (make sure it's empty)
+systemctl stop log2ram
+systemctl disable log2ram
+systemctl stop armbian-ramlog.service
+systemctl disable armbian-ramlog.service
+systemctl stop armbian-zram-config.service
+systemctl disable armbian-zram-config.service
+nano -w /etc/default/armbian-ramlog
+    # Disable
+nano -w /etc/default/armbian-zram-config
+    # Disable if *not* using swap in ram
+
+mv /var/log /var/oldlog
+mkdir /var/log
+rsync -aPr /var/oldlog/ /var/log/
+systemctl reboot
+
+```

advanced/zfs.md

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+# ZFS
+
+How to setup zfs on 64 bit arm boards.
+
+*Note: this is wholly untested and likely to be broken on 32 bit arm boards*
+
+## Initial Install / Setup
+
+``` bash 
+
+apt-add-repository universe
+apt install zfs-dkms spl-dkms zfsutils-linux
+cat > /etc/modprobe.d/zfs.conf <<EOF
+# Minimize RAM pain
+#options zfs zfs_arc_max=268435456 zfs_arc_meta_limit=201326592
+options zfs zfs_arc_max=134217728 zfs_arc_meta_limit=67108864
+#options zfs zfs_arc_max=100663296 zfs_arc_meta_limit=50331648
+EOF
+
+```
+
+## Disk Setup and Pool Creation
+
+Partition the disk and setup the zfs pool with basic settings
+
+``` bash
+
+parted /dev/disk/by-id/ata-Samsung_Portable_SSD_T5_S3UKNP0K601164R
+  mklabel gpt
+  mkpart
+zpool create -o ashift=12 \
+     -O copies=2 \
+     -O atime=off -O compression=lz4 \
+     -O normalization=formD \
+     tank \
+       /dev/disk/by-id/usb-JMicron_Tech_0000000055A1-0\:0-part1
+
+zpool status
+
+cat /sys/module/zfs/parameters/zfs_arc_max
+cat /sys/module/zfs/parameters/zfs_arc_meta_limit
+
+```
+
+## zfs Backed Swap
+
+Move swap from zram to zfs volumes on disk
+
+``` bash
+
+zfs create tank/swap
+zfs create -V 1G -b $(getconf PAGESIZE) -o compression=zle \
+      -o logbias=throughput -o sync=always \
+      -o primarycache=metadata -o secondarycache=none \
+      -o com.sun:auto-snapshot=false tank/swap/swap.1
+zfs create -V 1G -b $(getconf PAGESIZE) -o compression=zle \
+      -o logbias=throughput -o sync=always \
+      -o primarycache=metadata -o secondarycache=none \
+      -o com.sun:auto-snapshot=false tank/swap/swap.2
+
+mkswap -f /dev/zvol/tank/swap/swap.1
+mkswap -f /dev/zvol/tank/swap/swap.2
+echo /dev/zvol/tank/swap/swap.1 none swap defaults 0 0 >> /etc/fstab
+echo /dev/zvol/tank/swap/swap.2 none swap defaults 0 0 >> /etc/fstab
+swapon -af
+
+nano -w /etc/fstab # Add above swap and remove exiting ones
+
+nano -w /etc/default/armbian-zram-config
+    # Disabe if NOT using /var/log in RAM
+
+```
+
+## Regular scrubs and integrity checks
+
+``` bash
+
+crontab -e
+22 0 14 * * /sbin/zpool scrub tank
+
+```
+
+## Bulk storage and Samba filesystem shares
+
+``` bash
+
+# Samba toolchain
+apt install samba tdb-tools
+
+# Samba user setup
+useradd -g users -s /usr/sbin/nologin [username]
+passwd [username]
+smbpasswd -a [username]
+
+nano -w /etc/samba/smb.conf
+workgroup = non-default
+comment out all share definitions
+
+systemctl restart smbd
+
+# Bulk storage for all the things
+zfs create -o sharesmb=on tank/downloads
+zfs create -o sharesmb=on tank/scratch
+
+cat /var/lib/samba/usershares/*
+
+```