~talos/lug-zfs

ab6e1e61304ae94f7e8c0f6429508d7f884d6a9a — Jordan Newport 1 year, 2 months ago master
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A  => Makefile +13 -0
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LATEX = xelatex
TARGETS = slides.pdf

all: $(TARGETS)

%.pdf: %.tex lug.cls
	$(LATEX) -shell-escape $<
	while grep 'Rerun to get ' $*.log ; do $(LATEX) -shell-escape $<; done

clean:
	rm -f $(TARGETS)
	rm -f *.log *.nav *.aux *.out *.snm *.toc *.vrb
	rm -rf _minted-*

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A talk about ZFS for the Mines Linux User Group (see slides for details).

The slides are CC-by-SA.

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A  => graphics/freebsd.png +0 -0
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\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{lug}[2017/10/18]

\LoadClass{beamer}

\usetheme[numbering=none,progressbar=frametitle,block=fill]{metropolis}
\setbeamercovered{dynamic}
\RequirePackage{graphicx}

\RequirePackage{ifxetex}
\ifxetex\RequirePackage{fontspec}\fi

\RequirePackage{minted}
\RequirePackage{xcolor}
\RequirePackage{hyperref}

\renewcommand*\footnoterule{}
\setminted{autogobble,python3,mathescape}

\beamertemplatenavigationsymbolsempty%
\def\logoimage{graphics/lug}

\setlength\parindent{0pt}

\AtBeginDocument{%
    \begin{frame}
        \maketitle
    \end{frame}
}

\AtEndDocument{%
    \begin{frame}{Copyright Notice}
        \begin{columns}
            \begin{column}{0.7\textwidth}
                \small
                This presentation was from the \textbf{Mines
                Linux Users Group}. A mostly-complete archive of our
                presentations can be found online at
                \url{https://lug.mines.edu}.

                \bigskip

                Individual authors may have certain copyright or licensing
                restrictions on their presentations. Please be certain to
                contact the original author to obtain permission to reuse or
                distribute these slides.
            \end{column}

            \begin{column}{0.3\textwidth}
                \includegraphics[width=\textwidth]{\logoimage}
            \end{column}
        \end{columns}
    \end{frame}
}


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% vim: tw=500
\documentclass{lug}

\usepackage{fontspec}
\usepackage{hyperref}
\usepackage{graphicx}

\title{ZFS}
\author{Jordan Newport}

\begin{document}

\section{Introduction}

% why am I giving this talk? I have an obsession with Z-branded computing products.
% zfs, zsh, zathura, z workstations (z2 mini, zbook 15), zcentral remote boost...

% really, though, lots of cool features that make it good to use, particularly for servers (imo)

\begin{frame}{What is ZFS?}
    \begin{itemize}
        \item Originally the ``Zettabyte File System''; now just known as ZFS % that didn't stick
        \item ZFS is a filesystem with a lot of cool features
        \item ZFS is {\em also} a volume manager
        \item Doing both gives ZFS access to some cool features % and some performance benefits for those features
    \end{itemize}
\end{frame}

\begin{frame}{Goals of this talk}
    You should...
    \begin{itemize}
        \item be familiar with the basics of ZFS
        \item hear about some cool features that inspire you to compose them in brand new ways, UNIX-style
        \item be able to communicate intelligently about ZFS % you know, instead of being the noob you are right now
        \item think ZFS is cool, so you want to play with it % whether or not you actually have a specific need to
        \item have resources to learn more
    \end{itemize}
    \pause

    You should NOT...
    \begin{itemize}
        \item come out of this knowing a crapton of console commands and flags
    \end{itemize}
\end{frame}

\begin{frame}{Which ZFS? Or, a quick history}
    \begin{itemize}[<+->]
        \item ZFS was originally made for Sun's Solaris operating system. Work started in 2001 and it was released in 2004.
        \item ZFS was open-sourced as part of the OpenSolaris project from 2005-2010.
    \end{itemize}


\end{frame}

\begin{frame}
    % Enter Larry Ellison and his yacht obsession.
    \includegraphics[width=1.0\textwidth]{graphics/Rising_Sun_(yacht)_2006.jpg}
    \tiny
    image by Flickr user reivax - https://www.flickr.com/photos/reivax/349438581/in/photostream/, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=22867828
\end{frame}

\begin{frame}{A Quick History, continued}
    \begin{itemize}[<+->]
        \item Oracle bought Sun and closed-sourced ZFS in 2010
        \item The OpenZFS projectwas created in 2013 to manage development efforts on the core of ZFS, after people forked it
        \item OpenZFS is open source under the CDDL, which is copyleft but not viral
        \item Platforms maintain their own interfaces
        \item Oracle ZFS and OpenZFS are no longer compatible
    \end{itemize}
\end{frame}

\begin{frame}{A quick digression: ZFS on Linux}
    \begin{itemize}
        \item Used to be considered bad because of subtle incompatibilities between Linux ZFS and {\em everyone else's}
        \item This meant you could bork shared pools
        \item I haven't researched this in specific, but the zeitgeist suggests that ZFS on Linux is good now % or that there are ways to dodge the badness
        \item Due to some arcane combination of license incompatibilities and the relative newness of good support, ZFS is not as available as you might hope
        \item You might even have to load the kernel module yourself!
        \item \texttt{zfs-linux} in the AUR
        \item Ubuntu has some kind of special thing
    \end{itemize}

    % \includegraphics[width=0.1\textwidth]{graphics/freebsd.png}
\end{frame}

\begin{frame}{A quick digression: ZFS on Linux}
    \begin{itemize}
        \item Used to be considered bad because of subtle incompatibilities between Linux ZFS and {\em everyone else's}
        \item This meant you could bork shared pools
        \item I haven't researched this in specific, but the zeitgeist suggests that ZFS on Linux is good now % or that there are ways to dodge the badness
        \item Due to some arcane combination of license incompatibilities and the relative newness of good support, ZFS is not as available as you might hope
        \item You might even have to load the kernel module yourself!
        \item \texttt{zfs-linux} in the AUR
        \item Ubuntu has some kind of special thing
    \end{itemize}

    \includegraphics[width=0.1\textwidth]{graphics/freebsd.png} % or you could just use FreeBSD. You heathens

    % this is the BUG now
    % BSD user group
\end{frame}

\begin{frame}{So what is a filesystem?}
    You want to store some information.

    Your filesystem will help in some or all of these ways:
    \begin{itemize}[<+->]
        \item Organizes your storage medium into physical units
        \item Organizes units into named files
        \item Supports a (hierarchical) directory structure
        \item Stores metadata on files
        \item Provides some kind of interface to let you interact with these things % and, say, make or read files
            % acls, encryption, whatever
            % all this may include disk operations
            % internal utilities, user utilities, apis
        \item Maintains integrity, does backups, handles errors
    \end{itemize}
\end{frame}

\begin{frame}{So what is a volume manager?}
    You have one or more physical volumes or partitions thereof.

    The volume manager turns this into some number of logical volumes that can be presented to a filesystem.

    Not every system has a serious volume manager, but if yours does, here's what it will do:

    \begin{itemize}[<+->]
        \item Provide/manage redundancy
        \item Improve performance via ``striping''
        \item Resize logical volumes, possibly live with an online filesystem
    \end{itemize}

    % zfs!

\end{frame}

\begin{frame}{ZFS}
    3 goals:
    \begin{itemize}
        \item Data integrity % your data should not be corrupted
        \item Pooled storage % in a moment
        \item Performance % these features should be offered with >= performance to other filesystems
    \end{itemize}
\end{frame}

\section{\texttt{zpool}}

\begin{frame}{Zpool}
    Zpool is the volume-management half of ZFS.

    Zpool makes block devices into pools, which are just aggregations of one or more disks.

    Making a pool is as simple as

    \texttt{zpool create poolname [devices]}.

    You specify mirroring/RAID at creation time. % explained soon
\end{frame}

\begin{frame}{Redundancy and integrity}
    \begin{itemize}[<+->]
        \item ZFS has something called RaidZ, which is just a set of RAID options with better performance since it's integrated with the filesystem
        \item ZFS also has mirroring % literally just exact copies
        \item You can set up a pool of hot spares % pools fail over into these disks until you replace/promote them
        \item ZFS has pool-level checksumming and automatic repair % if in mirror or raid
        \item ZFS makes it trivial to replace both working and failed devices
    \end{itemize}
\end{frame}

\begin{frame}{Backups}
    \begin{itemize}[<+->]
        \item You can import or export pools between machines or on the same machine % this can be live
        \item Pools can be checkpointed % like a dataset snapshot
        \item Pools can be split or de-redudancied at any time
    \end{itemize}
\end{frame}

\begin{frame}{Performance}
    \begin{itemize}[<+->]
        \item Pools can have cache devices
    \end{itemize}
\end{frame}

\begin{frame}{Properties}
    These can all be set at creation, import, or even while running.
    \begin{itemize}[<+->]
        \item Readonly
        \item Autoexpand
        \item Autoreplace
        \item Permissions delegation
    \end{itemize}
\end{frame}

\begin{frame}{Devices}
    Devices can be added or removed at any time.

    They can be added as new mirrors, or they can be added to existing mirrors/non-redundant pools to expand the pool.

    Devices can be turned on or off at any time.
\end{frame}

\begin{frame}{Administration}
    Zpool and ZFS admin ops can be run as LUA scripts via zfs-program.

    This is in addition to cron. % or whatever systemd monstrosity you come up with on Linux
\end{frame}

\section{\texttt{zfs}}

\begin{frame}{ZFS}
    ZFS is the filesystem half of the ZFS system.

    It creates filesystems on top of zpools.

    This is as simple as

    \texttt{zfs create poolname/filesystem-name}.

    ZFS is copy-on-write. This means that when you write a file, it's actually copied, so that the original data is never lost.

    % this makes snapshots easy because you have an easy way to store only modified data in the snapshot

    % fyi: a lot the suggested use cases of these features are related to compression
\end{frame}

\begin{frame}{Datasets}
    Filesystems are known in ZFS as datasets.

    \pause

    It is not clear why.

    \pause

    % I *am* mostly going to call them datasets, because that's what the docs call them

    You can make and destroy datasets at any time. They may be nested inside other datasets.

    Datasets grow up to the size of the pool. All datasets in a shared pool may grow until their total size reaches the size of a pool.
    % what this means is that you don't have to preallocate dataset sizes; they just grow until they can't

    You can make ``volume'' datasets, which are block devices and can be used for other filesystems.
\end{frame}

\begin{frame}{Dataset management}
    \begin{itemize}[<+->]
        \item Datasets can be renamed
        \item This allows them to be given different parents and moved between pools.
            % different parents -> different inherited properties
        \item Dataset properties can be changed at any time
            \begin{itemize}
                \item ACL stuff
                \item Readonly
                \item NFS share
            \end{itemize}
        \item Just like pools, datasets have good ACL control and delegation of permissions
        \item Datasets also interact well with FreeBSD jails if you're into that
    \end{itemize}
\end{frame}

\begin{frame}{Snapshots}
    Snapshots are arguably the ``killer feature'' of ZFS.

    \begin{itemize}[<+->]
        \item Snapshots are per-dataset % (not per-file or directory)
        \item Snapshots are stored as diffs between the current filesystem state and the filesystem state when they were taken
            % storage using only the changed parts of COW
            % this means they grow as you change more things, but start at 0
        \item This means that for many use cases, snapshots will be very storage-efficient
        \item Because of their small size and effective storage, snapshots can be rolled back live, and in a safe and consistent fashion
            % explain consistency?
        \item You can diff between different snapshots % no specific differences, but will show what files were added/deleted/changed
        \item Not only can you roll back snapshots, you can roll back individual files from snapshots as well
    \end{itemize}
\end{frame}

\begin{frame}{More on snapshots}
    \begin{itemize}[<+->]
        \item Snapshots can also be cloned, which basically just copies the entire filesystem
        \item Snapshots can also be sent to other datasets to be restored using \texttt{zfs send}
        \item They canalso be piped directly to \texttt{zfs receive} on a live, running filesystem
        \item This can also be done over ssh
    \end{itemize}
\end{frame}

\begin{frame}{Pool space}
    \begin{itemize}[<+->]
        \item You can set quotas for datasets, users, and groups
        \item You can also reserve a certain amount of space for a dataset % for, say, important growing files or log files
    \end{itemize}
\end{frame}

\begin{frame}{Compression}
    \begin{itemize}[<+->]
        \item It's very easy to create a compressed dataset
        \item New versions of ZFS have very good compression
        \item ZFS 5000 has LZ4 compression and basically no performance tradeoff
            \begin{itemize}
                \item Writing compressed data improves your disk IO situation % which balances the time you needed to compress
                \item If ZFS detects that it's not compressing enough on the first block, then it aborts compression and writes uncompressed % to save time
            \end{itemize}
        \item Deduplication also exists, although compression is almost always better % noting copies of existing blocks rather than rewriting them
    \end{itemize}
\end{frame}

\section{Resources}

\begin{frame}{Resources}
    The Wikipedia page for ZFS is the source of a lot of the background.

    The two resources I looked at for technical content are (hyperlinks):

    \begin{itemize}
        % FreeBSD man pages have a reputation as being mildly better than Linux ones, and ZFS is first-class on FreeBSD
        \item The FreeBSD man pages for \href{https://www.unix.com/man-page/freebsd/8/zpool/}{zpool},
            \href{https://www.unix.com/man-page/freebsd/8/zfs/}{zfs},
            and \href{https://www.unix.com/man-page/freebsd/8/zfs-program/}{zfs-program}
        \item The \href{https://docs.freebsd.org/en/books/handbook/zfs/}{FreeBSD System Administration Handbook's ZFS section}
    \end{itemize}
\end{frame}

\end{document}