Posscon2013

Introduction to
FreeNAS 8.3.1

Dru Lavigne
Documentation Lead, iXsystems
POSSCON, March 27, 2013

Class Outline

USB key contains the 32- and 64-bit ISOs of
FreeNAS 8.3.1, a PDF version of the 8.3.1 Users
Guide, and a PDF of this presentation.

If you would like to follow along by installing
FreeNAS into a virtual machine, create several
virtual disks. Instructions for doing so in Virtualbox
can be found on pp 21-28 of the PDF. If your CPU
does not support “long mode”, use the 32-bit ISO.

Outline

✔ FreeNAS Overview

ZFS Overview

Configuration Workflow

Plugins Overview

ZFS Encryption Overview

Additional Resources

FreeNAS Overview

Open source NAS (network attached storage)
based on an embedded version of FreeBSD
(nanoBSD) and released under 2-clause BSD
license

Enterprise-grade appliance (TrueNAS) is also
available in 2U/4U form factors with professional
support

FreeNAS Overview
8.x is a rewrite of the original monolithic design to
a modular design (.7x EOL'd in 2011)

8.0 was released May, 2011 with a focus on NAS
“core” functionality

8.2.0 introduced the Plugins Jail architecture
(released on July 20, 2012) for extending core

8.3.1 added GELI encryption for ZFS pools
(released March 20, 2013)

Core Features
Create UFS or ZFS volumes (ZFS recommended)

Import existing UFS/ZFS RAID/z volumes

Import existing UFS, DOS, NTFS, EXT2/3
volumes

Create shares using Appletalk, NFS, and SMB
protocols

Configure access through FTP/SFTP, SSH, and
iSCSI

Core Features

Integration with OpenLDAP, Active Directory

Automated, secure replication via rsync/ssh

Automated ZFS snapshots and scrubs

Front-ends to cron, sysctls, loader.conf

Reporting graphs, scheduled S.M.A.R.T. tests,
automated alerts, UPS

Core Features

Link aggregation, failover, and VLAN support

DDNS, SNMP, and TFTP support

Control panel to stop/start and view the status of
services

Users Guide available in wiki, HTML, PDF, epub,
and Kindle formats

Core Features
Supports OSX Time Machine and Windows
Shadow Copies

OS is installed on USB stick/CF and is separate
from data on storage disks

Upgrades keep a backup of the old OS, allowing
for rollback

Administrative GUI accessed through a web
browser; 8.2 adds a web shell for command line
operations

ZFS Overview

128-bit filesystem with a maximum pool/file size of
16 exabytes

Unlike traditional Unix filesystems, you are not
limited to the partition size and mount point
defined at filesystem creation time

Instead, disks are fed to a “pool” and the size of
that pool can increase as disk capacity increases

ZFS Overview

The pool can be logically subdivided, with each
segment having access to the remaining capacity
of the pool

Offers great flexibility!

Pre-planning for hardware and designing for a
particular environment's storage needs is needed
for optimization and to get the full benefits of ZFS

Pool
Root (parent) volume which can be sub-divided
into datasets or zvols as needed

Typically only one, but multiple pools are allowed

Typically, feed all disks to the pool

The number of disks added at a time is known as
a “vdev”

To optimize performance, number of disks is
limited and additional vdevs are striped

RAIDZ
RAIDZ* levels designed to overcome hardware
RAID limitations such as the write-hole and
corrupt data written over time before the controller
notices

Designed for commodity disks so no RAID
controller is needed

Can also be used with a RAID controller, but it
should be put in JBOD mode

RAIDZ1
Avoids the RAID5 write-hole by using COW (copy
on write)

Parity blocks are distributed across all disks

Up to one disk can fail without losing pool

Pool can be lost if second disk fails before restripe
completes

Optimized for vdev of 3, 5, or 9 disks

RAIDZ2

Double-parity solution similar to RAID6


Up to two disks can fail without losing pool, with
no restrictions on which disks can fail


RAIDZ3

Triple-parity solution


Up to three disks can fail without losing pool, with
no restrictions on which disks can fail


ZIL

ZFS Intent Log

Effectively a filesystem journal that manages
writes

A dedicated SSD or drive can increase write
performance, especially for synchronous NFS

Use ZFSv28 for dedicated ZIL or else lost device
will lose pool

ARC
ARC refers to read cache in RAM; if RAM is very
small, read speed is reduced to disk speed

Expect a miss for random reads and a hit for
cached reads

Takes time for ARC to populate; if high misses
continue for cached reads, the system needs to
be tuned

Freenas adds ARC stats to top(1) and includes
arc_summary.py and arcstat.py tools for ARC
monitoring

L2ARC

Optional, secondary ARC which can be installed
on SSD or disk

L2ARC is populated over time with “hot” reads

Recommended for deduplication and to increase
read performance

Datasets

Pool can be divided into datasets

Similar to a folder in that it supports permissions

Similar to a filesystem in that you can set
properties such as quotas and compression

A well thought out design can optimize storage for
the type of data being stored

Zvols

Pool can also be divided into zvols

Essentially, a virtual, raw block device

Ideal for iSCSI device extents

Supports quotas and compression

Snapshots
Provide read-only, point-in-time image of the
specified pool, dataset, or zvol

Snapshots can be recursive (atomic inclusion of
all child datasets)

Initial size is 0 bytes as COW, snapshot increases
in size as changes are written to disk

Can be replicated to another system

Can be used to provide Windows shadow copies

Clones

Provide read-write copies of read-only snapshots

Initial size of clone is 0 bytes

Clones can be mounted and used to access data
from that point in time (e.g. earlier revision of a
file)

Scrubs
ZFS was designed to be self-healing

ZFS creates and verifies checksums as data is
written to disk

A scrub verifies the checksum in each disk block,
correcting data as necessary

I/O intensive so should be scheduled
appropriately

Reading the scrub results can provide an early
indication of possible disk failure

Deduplication

Used to free blocks containing identical data
(updates reference pointers)

Can improve performance on datasets containing
duplicate data (e.g. virtual images)

Dedup tables should fit into L2ARC; systems with
limited RAM or no L2ARC might freeze hard

RAM
RAM is used to hold read cache, write cache,
checksum calculations, dedup tables, parity
calculations, etc.

Add as much RAM as possible; general rule of
thumb is:

1 GB of RAM for every 1TB of storage in pool

5 GB RAM/L2ARC per TB of storage to be
deduplicated (use a dataset)

Misc
zpool split command can be used to “clone” a
mirror to one disk and to use that disk to recreate
that pool on a different system

autoexpand property allows pool to grow by
replacing one disk at a time with a larger disk

Resilvering is the process of resyncing a RAIDZ.
This takes time, depending upon the size of disk
being replaced. It is a bad thing to lose the
maximum number of disks in a RAIDZ before the
resilver completes.

Configuration Workflow

1. Set the administrative username and password

2. Create volumes/datasets

3. Create users/groups or integrate with LDAP/AD

4. Configure share

5. Start applicable service(s)

6. Test and save the configuration

2. Create Volume
Several choices:

1. Import existing UFS RAID or ZFS pool

2. Import existing disk or partition(s) formatted
with UFS, FAT, NTFS, or EXT2/3

3. Format a UFS or ZFS volume

Once a ZFS volume (pool) is created, it can be
divided into datasets (with own options) or zvols
(to use as a “raw” disk for iSCSI)

3. Users/Groups

Choices:

1. Manually create

2. Import existing Active Directory users

3. Import existing LDAP users

4. Configure Share
AFP: for Mac OS X

CIFS: for Windows, also supports any other OS

NFS: faster than CIFS, supports any OS

SSH: CLI and GUI clients available for any OS

FTP: CLI and GUI clients available for any OS

iSCSI target: for access to “raw” disks

Configure Share

When configuring:

Recommended to only have one type of share to
prevent filesystem/client conflicts

Users needing access to that share must have
permission to the volume being shared, or the
share access must be set to anon/guest

Permissions can be set on a per volume or per
dataset basis

6. Test and Save Configuration

From a client, confirm that access is permitted to
allowed users

Can enable console logging at bottom of browser
to troubleshoot a service that won't start

Can use web shell to read logs when
troubleshooting

Plugins Architecture

Provides the administrator the flexibility to install
additional software from the FreeNAS GUI to
meet the requirements of the NAS

Comprised of three components:

- FreeBSD Jail

- PBI (Push Button Installer) files

- Plugins

What is a Jail?

A FreeBSD feature for providing light-weight,
operating system-level virtualization

A jail has its own hostname, IP address, users,
and is separated from the host operating system

FreeNAS implementation includes vimage which
gives the jail its own networking stack and IP
broadcasting

What is a PBI/Plugin?
PBI format originally created by the PC-BSD
project (a desktop version of FreeBSD)

Provides a graphical installation wrapper for
software ported to FreeBSD

FreeNAS implementation extends this
functionality by incorporating the application's
configuration file into the FreeNAS graphical
administrative interface—the result is known as a
Plugin

Installing the Plugins Jail
Before any plugins can be installed, the Plugins
Jail must be installed and started

Recommended that Plugins Jail is installed into its
own ZFS dataset and that a second dataset is
used to store the installed software

The Plugins Jail and supported Plugins can be
downloaded from plugins folder for architecture
http://sourceforge.net/projects/freenas/files/
FreeNAS-8.3.1/

Installing a Plugin

Once the Plugins Jail is installed and the Plugins
service started, you can install FreeNAS PBIs
(Plugins)

As each Plugin is installed, an icon will be added
to the FreeNAS menu (used to configure the
application) and its service will be added to the
Plugins tab of the Control Services menu so it can
be started

Installing Non-PBI Software
If a PBI is not available, you can still install
FreeBSD packages or compile ports within the
Plugins Jail

Software installed this way will not be integrated
into the administrative interface but can be
configured and started from the command line

Use FreshPorts.org to search for software that
has been ported to FreeBSD

Installing Packages
A FreeBSD package is a pre-compiled binary that
includes the dependencies required by the
application

Installed using the pkg_add -r command:
FreshPorts.org will tell you the exact command to
use

pkg_info -Lx will tell you what gets installed

Typically, conf files are in /usr/local/etc/ and
startup scripts are in /usr/local/etc/rc.d/

Compiling Ports
Packages are recommended unless a package is
not available or you need to change a compile
option as compiling takes time and system
resources

FreshPorts.org will list the available compile
options

Use the make install command to compile

Once compiled and installed, the software can be
configured like any other package

Available PBIs
FreeNAS PBIs are still new (only available since
July 2012)

3 official PBIs: Firefly, MiniDLNA, Transmission

List of PBI requests:
http://doc.freenas.org/index.php/PBI_Requests

List of user-created PBIs:
http://forums.freenas.org/showthread.php?8470-
INDEX-Available-Plugins

Encryption
GELI full disk encryption for new ZFS volumes
(not ZFSv30 encryption which is closed source)

Full disk encryption, not per-filesystem encryption

Targeted at users who store sensitive data and
want the ability to safely dispose of disks
(independent of the encryption key) without wiping
them first

Encryption key is per ZFS pool

Encryption
Encryption key is protected by both a passphrase
and a recovery key

CPU that supports AES-NI is recommended,
especially if more than one disk in pool

Data in the ARC cache and the contents of RAM
are unencrypted

Swap is always encrypted, even on unencrypted
volumes

Encryption

Key management tools added to encrypted
volume's screen in GUI

Used to change the passphrase, download a copy
of the key, create a new key (which destroys the
old key), create and download a copy of the
recovery key, and change the recovery key

If the passphrase is forgotten, the recovery key
can be used (needed when importing a pool)

Resources

Website:

http://www.freenas.org

Forums:

http://forums.freenas.org

Bug tracker:

http://support.freenas.org

Resources
Links to Users Guide:

http://doc.freenas.org

IRC:

#freenas on Freenode

Links to mailing lists and instructional videos:

http://doc.freenas.org/index.php/
FreeNAS_Support_Resources

Questions

Contact:

dru@freebsd.org

URL to Slides:

http://slideshare.net/dlavigne/posscon2013

Posscon2013

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