Plus our favorite features from Fedora 32, and why Wes loves DNF.

Links:

• What's new in Fedora 32 Workstation
• Fedora 32 ChangeSet
• Linux distro review: Fedora Workstation 32
• TechSNAP 428: RAID Reality Check
• ZFS versus RAID: Eight Ironwolf disks, two filesystems, one winner
• Understanding RAID: How performance scales from one disk to eight
• Find Jim on 2.5 Admins
• Find Wes on LINUX Unplugged
• TechSNAP 1: First episode of TechSNAP (in 2011!)
• TechSNAP 300: End of the Allan and Chris era (2017)
• TechSNAP 301: Enter Dan and Wes
• TechSNAP 347: A Farewell to Dan
• TechSNAP 348: Chris is back!
• TechSNAP 389: Jim's first time as a guest
• TechSNAP 390: Jim's second guest appearance
• TechSNAP 393: Chris says goodbye
• TechSNAP 395: Jim joins the show

Plus an update on ZoL SIMD acceleration, your feedback, and an interesting new neuromorphic system from Intel.

Links:

• ZFS On Linux Has Figured Out A Way To Restore SIMD Support On Linux 5.0+ — Those running ZFS On Linux (ZoL) on post-5.0 (and pre-5.0 supported LTS releases) have seen big performance hits to the ZFS encryption performance in particular. That came due to upstream breaking an interface used by ZFS On Linux and admittedly not caring about ZoL due to it being an out-of-tree user. But now several kernel releases later, a workaround has been devised.
• ZFS On Linux Runs Into A Snag With Linux 5.0
• NixOS Takes Action After 1.2GB/s ZFS Encryption Speed Drops To 200MB/s With Linux 5.0+ — A NixOS developer reports that the functions no longer exported by Linux 5.0+ and previously used by ZoL for AVX/AES-NI support end up dropping the ZFS data-set encryption performance to 200MB/s where as pre-5.0 kernels ran around 1.2GB/s
• Linux 5.0 compat: SIMD compatibility · zfsonlinux/zfs@e5db313 — Restore the SIMD optimization for 4.19.38 LTS, 4.14.120 LTS, and 5.0 and newer kernels. This is accomplished by leveraging the fact that by definition dedicated kernel threads never need to concern themselves with saving and restoring the user FPU state. Therefore, they may use the FPU as long as we can guarantee user tasks always restore their FPU state before context switching back to user space.
• no SIMD acceleration · Issue #8793 · zfsonlinux/zfs — 4.14.x, 4.19.x, 5.x all have no SIMD acceleration, it is like a turtle. very slow.
• Chris's Wiki :: ZFS on Linux still has annoying issues with ARC size — One of the frustrating things about operating ZFS on Linux is that the ARC size is critical but ZFS's auto-tuning of it is opaque and apparently prone to malfunctions, where your ARC will mysteriously shrink drastically and then stick there.
• Software woven into wire, Core rope and the Apollo Guidance Computer — One of the first computers to use integrated circuits, the Apollo Guidance Computer was lightweight enough and small enough to fly in space. An unusual feature that contributed to its small size was core rope memory, a technique of physically weaving software into high-density storage.
• Virtual Apollo Guidance Computer (AGC) software — Since you are looking at this README file, you are in the "master" branch of the repository, which contains source-code transcriptions of the original Project Apollo software for the Apollo Guidance Computer (AGC) and Abort Guidance System (AGS), as well as our software for emulating the AGC, AGS, and some of their peripheral devices (such as the display-keyboard unit, or DSKY).
• The Underappreciated Power of the Apollo Computer - The Atlantic — Without the computers on board the Apollo spacecraft, there would have been no moon landing, no triumphant first step, no high-water mark for human space travel. A pilot could never have navigated the way to the moon, as if a spaceship were simply a more powerful airplane. The calculations required to make in-flight adjustments and the complexity of the thrust controls outstripped human capacities.
• Brains scale better than CPUs. So Intel is building brains | Ars Technica — Neuromorphic engineering—building machines that mimic the function of organic brains in hardware as well as software—is becoming more and more prominent. The field has progressed rapidly, from conceptual beginnings in the late 1980s to experimental field programmable neural arrays in 2006, early memristor-powered device proposals in 2012, IBM's TrueNorth NPU in 2014, and Intel's Loihi neuromorphic processor in 2017. Yesterday, Intel broke a little more new ground with the debut of a larger-scale neuromorphic system, Pohoiki Beach, which integrates 64 of its Loihi chips.
• Dancing Demon - YouTube — Written in 1979 by Leo Christopherson for the Radio Shack TRS-80 Model I computer. This is the best game ever for at that time.

Plus Firefox zero days targeting Coinbase, the latest update on Rowhammer, and a few more reasons it's a great time to be a ZFS user.

Links:

• SACK Panic Security Bulletin — Netflix has identified several TCP networking vulnerabilities in FreeBSD and Linux kernels. The vulnerabilities specifically relate to the Maximum Segment Size (MSS) and TCP Selective Acknowledgement (SACK) capabilities. The most serious, dubbed “SACK Panic,” allows a remotely-triggered kernel panic on recent Linux kernels.
• Ubuntu SACK Panic Guidance — You should update your kernel to the versions specified below in the Updates section and reboot. Alternatively, Canonical Livepatch updates will be available to mitigate these two issues without the need to reboot.
• Red Hat SACK Panic Advisory — Red Hat customers running affected versions of these Red Hat products are strongly recommended to update them as soon as errata are available. Customers are urged to apply the available updates immediately and enable the mitigations as they feel appropriate.   
• RFC 2018 - TCP Selective Acknowledgment Options — TCP may experience poor performance when multiple packets are lost from one window of data. With the limited information available from cumulative acknowledgments, a TCP sender can only learn about a single lost packet per round trip time. An aggressive sender could choose to retransmit packets early, but such retransmitted segments may have already been successfully received. A Selective Acknowledgment (SACK) mechanism, combined with a selective repeat retransmission policy, can help to overcome these limitations.
• Ping of Death — In a nutshell, it is possible to crash, reboot or otherwise kill a large number of systems by sending a ping of a certain size from a remote machine.
• Firefox zero-day was used in attack against Coinbase employees, not its users | ZDNet — A recent Firefox zero-day that has made headlines across the tech news world this week was actually used in attacks against Coinbase employees, and not the company's users.
• Mozilla fixes second Firefox zero-day exploited in the wild | ZDNet — Mozilla has released a second security update this week to patch a second zero-day that was being exploited in the wild to attack Coinbase employees and other cryptocurrency organizations.
• RAMBleed — RAMBleed is a side-channel attack that enables an attacker to read out physical memory belonging to other processes. The implications of violating arbitrary privilege boundaries are numerous, and vary in severity based on the other software running on the target machine. As an example, in our paper we demonstrate an attack against OpenSSH in which we use RAMBleed to leak a 2048 bit RSA key.
• Digging into the new features in OpenZFS post-Linux migration | Ars Technica — One of the most important new features in 0.8 is Native ZFS Encryption. Until now, ZFS users have relied on OS-provided encrypted filesystem layers either above or below ZFS. While this approach does work, it presented difficulties.
• Allan Jude on Twitter — Once the FreeBSDs are upstreamed, everything is changing to 'OpenZFS', including the github organization currently know as 'zfsonlinux'.
• ZFS on Linux Releases
• Linux Academy is hiring!
• Mozilla teases $5-per-month ad-free news subscription — Mozilla has started teasing an ad-free news subscription service, which, for $5 per month, would offer ad-free browsing, audio readouts, and cross-platform syncing of news articles from a number of websites.

Plus some handy tools to manage your snapshots, rsync war stories, and more!

Links:

• sanoid: Policy-driven snapshot management and replication tools. — Sanoid is a policy-driven snapshot management tool for ZFS filesystems. When combined with the Linux KVM hypervisor, you can use it to make your systems functionally immortal.
• Syncoid — Sanoid also includes a replication tool, syncoid, which facilitates the asynchronous incremental replication of ZFS filesystems.
• Copy-on-write - Wikipedia
• ZFS Paper
• The Magic Behind APFS: Copy-On-Write — The brand-new Apple File System (APFS) that landed with macOS High Sierra brings a handful of important new features that rely on a technique called copy-on-write (CoW).
• Chapter 19. The Z File System (ZFS)

Plus the nitty-gritty details of vectorized optimizations and kernel preemption, and our thoughts on the future of the relationship between ZFS and Linux.

Special Guest: Richard Yao.

Links:

• LinuxFest Northwest 2019 — Join a bunch of JB hosts and community celebrating the 20th anniversary!
• Choose Linux — The show that captures the excitement of discovering Linux.
• Linux 5.0: _kernel_fpu{begin,end} no longer exported — The latest kernels removed the old compatibility headers.
• ZFS On Linux Landing Workaround For Linux 5.0 Kernel Support — So while these symbols are important for SIMD vectorized checksums for ZFS in the name of performance, with Linux 5.0+ they are not going to be exported for use by non-GPL modules. ZFS On Linux developer Tony Hutter has now staged a change that would disable vector instructions on Linux 5.0+ kernels.
• Re: x86/fpu: Don't export __kernel_fpu_{begin,end}() — My tolerance for ZFS is pretty non-existant. Sun explicitly did not want their code to work on Linux, so why would we do extra work to get their code to work properly?
• The future of ZFS in FreeBSD — This state of affairs has led to a general agreement among the stakeholders that I have spoken to that it makes sense to rebase FreeBSD's ZFS on ZoL. Brian Behlendorf has graciously encouraged me to add FreeBSD support directly so that we might all have a singleshared code base.
• Dephix: Kickoff to The Future — OpenZFS has grown over the last decade, and delivering our application on Linux provides great OpenZFS support while enabling higher velocity adoption of new environments.
• The future of ZFS on Linux [zfs-discuss] — Do you realize that we don’t actually need the symbols that the kernel removed. It All they do is save/restore of register state while turning off/on preemption. Nothing stops us from doing that ourselves. It is possible to implement our own substitutes using code from either Illumos or FreeBSD or even write our own. Honestly, I am beginning to think that my attempt to compromise with mainline gave the wrong impression. I am simply tired of this behavior by them and felt like reaching out to put an end to it. In a few weeks, we will likely be running on Linux 5.0 as if those symbols had never been removed because we will almost certainly have our own substitutes for them. Having to bloat our code because mainline won’t give us access to trivial functionality is annoying, but it is not the end of the world.
• LINUX Unplugged Episode 284: Free as in Get Out
• BSD Now 279: Future of ZFS
• BSD Now 157: ZFS, The “Universal” File-system

Plus an update on the show and what to expect, and we attempt something TechSNAP could never do as a video production, a live double FreeNAS upgrade!

Sponsored By:

• Digital Ocean: Apply our promo snapocean after you create your account, and get a $10 credit. Promo Code: snapocean
• Ting: Save $25 off a device, or get $25 in service credits! Promo Code: Visit techsnap.ting.com
• iXSystems: Get a system purpose built for you. Promo Code: Tell them we sent you!

Links:

• Our New Contact Page
• Mirai IoT Botnet Co-Authors Plead Guilty — Krebs on Security — The U.S. Justice Department on Tuesday unsealed the guilty pleas of two men first identified in January 2017 by KrebsOnSecurity as the likely co-authors of Mirai, a malware strain that remotely enslaves so-called “Internet of Things” devices such as security cameras, routers, and digital video recorders for use in large scale attacks designed to knock Web sites and entire networks offline (including multiple major attacks against this site).
• Pre-Installed Keylogger Found On Over 460 HP Laptop Models — The Keylogger was found embedded in the SynTP.sys file, a part of Synaptics touchpad driver that ships with HP notebook computers, leaving more than 460 HP Notebook models vulnerable to hackers.
• HP keylogger - ZwClose Blog Post — TL;DR: HP had a keylogger in the keyboard driver. The keylogger saved scan codes to a WPP trace. The logging was disabled by default but could be enabled by setting a registry value (UAC required)
• Apple Releases iOS 11.2.1 Update With HomeKit Fix — According to Apple's release notes, the update re-enables remote access for shared users of the Home app. Apple broke remote access for shared users when implementing a fix for a major HomeKit vulnerability last week.
• FreeNAS 11.1 Released — The FreeNAS Development Team is excited and proud to present FreeNAS 11.1! FreeNAS 11.1 adds cloud integration, OpenZFS performance improvements, including the ability to prioritize resilvering operations, and preliminary Docker support to the world’s most popular software-defined storage operating system. This release includes an updated preview of the beta version of the new administrator graphical user interface, including the ability to select display themes. This post provides a brief overview of the new features.
• Process Doppelgänging Attack — Dubbed ‘Process Doppelgänging‘ by Tal Liberman and Eugene Kogan of EnSilo, the attack was demonstrated during Black Hat Europe 2017 security conference in London earlier today. Doppelgänging, a fileless code injection technique, works in such a manner that an attacker can manipulate the way Windows handles its file transaction process and pass malicious files even if the code is known to be malicious.
• Process Doppelgänging - Black Hat Europe 2017 — By using NTFS transactions, we make changes to an executable file that will never actually be committed to disk. We will then use undocumented implementation details of the process loading mechanism to load our modified executable, but not before rolling back the changes we made to the executable. The result of this procedure is creating a process from the modified executable, while deployed security mechanisms in the dark.