Getting Started with unRAID Server OS

So are you ready to get started?  Great!  You’ve come to the right place!  In this guide we will be covering how to prepare your flash device, boot the system, and configure your first array.  The entire process should take less than 15 minutes.

Prerequisites

Before we begin, you should have your server assembled, connected via power and Ethernet, and you should have a monitor and keyboard attached for the initial configuration (to be ready to alter configuration settings in your BIOS).  Once the initial setup is complete, you can disconnect your monitor and keyboard to run unRAID in a “headless” state if you so desire.  You will also need a quality USB flash device that is 512MB or larger.  If you haven’t purchased your hardware yet, we have lots of recommendations.

Video Guides

Text-Based Guide

Preparing your USB Flash Device

• Insert the 512MB or larger flash device to your Mac or PC.
• Format the device using the FAT (or FAT32) file system.
• Set the ‘volume label’ to UNRAID (case-sensitive; all caps).
• Click here to go to the downloads page.
• Choose a version and download it to a temporary location on your computer (e.g. a “downloads” folder).
• Extract the contents of the newly downloaded ZIP file onto your USB flash device.
• Browse to the USB flash device to see the newly extracted contents from your Mac or PC.
• Run the make bootable script.
  • From Windows XP, just double-click the make_bootable file.
  • From Windows 7 or later, right-click the file and select ‘Run as Administrator’.
  • From Mac devices, double-click the file ‘make_bootable_mac’ and enter your admin password when prompted.
  • NOTE:  during the process of running this script, the flash device may seem to disappear and reappear on your workstation a few times – this is expected behavior.

Visual Guide (Screenshots)

Booting Up

You’re now ready to remove the Flash from your PC or Mac, plug it into your server, and power up.  If unRAID Server OS immediately boots (with some motherboards it will), you can skip ahead to assigning devices.  If it doesn’t boot, reset your server, enter the BIOS, set the system to boot from USB flash, save your BIOS settings, and try to booting again.  If you are still having difficulty getting your server to boot from the flash, ensure that the Flash is the only device plugged into any of the USB ports.  Also avoid using front panel USB ports in favor of ports available directly on the motherboard I/O panel.  If you’ve followed these guidelines and still can’t boot, try the following adjustments in your BIOS settings:

• Set the boot order to as follows:  Forced-FDD, USB-HDD, USB-ZIP
• Try disabling USB 2.0 support (this will default to USB 1.1).
• Try switching on or off any “Fast Boot” feature.
• Try Switching on or off “USB keyboard” support.

Assigning Devices to the Array and Cache

Now that you’ve booted up your unRAID Server, you are ready to begin setting up your first array.  The boot process shouldn’t take more than a few minutes and when completed, open a web browser from your Mac or PC and navigate to http://tower (or http://tower.local if using a Mac).  The first page you will be brought to is the unRAID Main tab, where you will select the devices to assign to slots for parity, data, and cache disks.  Assigning devices to unRAID is easy!  Just remember these guidelines:

Always pick the largest storage device available to act as your parity device.  When expanding your array in the future (adding more devices to data disk slots), you cannot assign a data disk that is larger than your parity device.  For this reason, it is highly recommended to purchase the largest HDD available for use as your initial parity device, so future expansions aren’t limited to small device sizes.

Do not assign an SSD as a data/parity device.  While unRAID won’t stop you from doing this, SSDs are only supported for use as cache devices due TRIM/discard and how it impacts parity protection.  Using SSDs as data/parity devices is unsupported and may result in data loss at this time.

Using a cache will improve array performance.  It does this by redirecting write operations to a dedicated disk (or pool of disks in unRAID 6) and moves that data to the array on a schedule that you define (by default, once per day at 3:40AM).  Data written to the cache is still presented through your user shares, making use of this function completely transparent.

New in unRAID 6:  Cache Pools and SSDs

Creating a cache-pool adds protection for cached data.  If you only assign one cache device to the system, data residing their before being moved to the array on a schedule is not protected from data loss.  To ensure data remains protected at all times (both on data and cache disks), you must assign more than one device to the cache function, creating what is called a cache-pool.  Cache pools can be expanded on demand, similar to the array.

SSD-based cache devices are ideal for applications and virtual machines.  Apps and VMs benefit from SSDs as they can leverage their raw IO potential to perform faster when interacting with them.  Use SSDs in a cache pool for the ultimate combination of functionality, performance, and protection.

IMPORTANT:  Your array will not start if you assign more devices than your license key allows.

Starting the Array and Formatting Your Devices

Once you have all your devices assigned, you can click the ‘Start’ button under ‘Array Operation.’  This will mount your devices and start the array.  New devices added to disk or cache device slots will appear as ‘Unformatted’ and will be unusable until you format them.  unRAID 6 defaults to using the XFS filesystem for all devices, but if you define a cache pool, BTRFS will automatically be used for those devices.  To format your devices for use, you must click the check box under ‘Array Operation’ that says ‘Format” and then click the ‘Format’ button.

Even before the devices are formatted, a ‘parity sync’ will be performing in the background to initialize the protection of the array.  Until the sync is completed, the array will operate but in an unprotected state.  It is recommended to wait until the initial parity sync completes before adding data to the array.