Un-edited Live session – http://www.youtube.com/watch?v=5gJL0nPoHEU
Tony Bemus, Mat Enders, and Mary Tomich
Sound bites by Mike Tanner
Kernel News: Mat
mainline: 3.18 2014-12-07 stable: 3.17.6 2014-12-07 longterm: 3.14.26 2014-12-06 longterm: 3.12.35 2014-12-10 longterm: 3.10.62 2014-12-06 longterm: 3.4.105 2014-12-01 longterm: 3.2.64 2014-11-05 longterm: 18.104.22.168 2014-12-13 linux-next: next-20141212 2014-12-12
Distro Talk: Tony
- 12-1 – Manjaro Linux 0.8.11
- 12-2 – Linux Lite 2.2
- 12-4 – antiX 14.3 “MX”
- 12-7 – MakuluLinux 7.0 “Xfce”
- 12-8 – SparkyLinux 3.6 “LXDE”, “MATE”, “Razor-qt”, “Xfce”
- 12-9 – Porteus 3.1
- 12-9 – FreeNAS 9.3
- 12-9 – Fedora 21
- 12-9 – Clonezilla Live 2.3.1-18
- 12-10 – Alpine Linux 3.1.0
- 12-13 – LinuxConsole 2.3
- 12-13 – Tanglu 2.0
Distro of the Week: Tony
- Debian – 1408
- openSUSE – 1419
- Ubuntu – 1595
- Mint – 2221
- Fedora – 2933
Mary Book Review
FreeBSD Mastery: Storage Essentials
By Michael W Lucas
I’m a fan of Michael W. Lucas and I am a new fan of PC-BSD which, of course, is FreeBSD under the hood. So it made perfect sense for me to review Lucas’ most recent book, FreeBSD Mastery: Storage Essentials.
FreeBSD Mastery: Storage Essentials was released in November 2014 by Tilted Windmill Press.
Lucas’ book starts with one of my favorite topic—Disks. He humorously titled the chapter-Chapter 0: Disks Suck. This chapter does double duty—it starts by Lucas laying a solid foundation about disks including quite a bit of detail about early file systems and and the tricks how disk manufacturers took advantage of a disk’s physical characteristics and used math tricks to increase the size/capacity of their drives—or give that appearance. It all depends on whether it’s measured in multiples of 1000 or powers of two. The devil’s in the details and the details are in the book. The rest of the chapter provides a mini-synopsis of each chapter in the book.
In Chapter 1: FreeBSD and Disks, Lucas introduces the reader to GEOM, In FreeBSD, the GEOM framework exists between the devices nodes, e.g. /dev/da0, and the disk’s device driver and handles the data exchanged between them. Lucas discusses individual instances of GEOM, also called geom ( lower case letters), that they can be stacked, taking the output of one class as the input for another geom. In this chapter, he also compares the capabilities of geoms and volume managers—they’re not the same. The unlimited flexibility of the geom is what really sets it apart.
Partitioning schemes are also covered in this chapter. Although there are several, two receive the lion-share of focus: MBR (master boot record) scheme and GPT (GUID partition table) scheme. Lucas notes the preference for GPT if you have modern hardware but he does not short shrift the MBR scheme which he covers in chapter 3.
Chapter 2: Using GUID Partition Tables Lucas opens this chapter by saying that GPT is the standard for partitioning on modern systems. Unlike MBR method with its slices and BSD partitions (which are covered in Chapter 3), the GPT method uses only uses partitions. All of the steps you need to set up a GPT disk are included and Lucas goes on to explain how FreeBSD tricks older hardware into using a GPT partition table by placing a PMBR or Protective MBR on the disk to give the older hardware a recognizable partition table and help it boot it.
Chapter 2 also contains a brief mention of the UEFI bootloader is mentioned here along with the cautionary note that the support for UEFI is in its early stages. But instructions are provided nonetheless, along with a suggestion of consulting the FreeBSD documentation.
Chapter 3: Using MBR Partitions – Lucas dives into this partition scheme in earnest in the third chapter, discussing the historical precedence for how FreeBSD held partition information. When it was ported to x86 hardware, FreeBSD had to contend with the MBR approach (maximum of four primary partitions—called slices in FreeBSD). Instead of adopting it, the FreeBSD project treated the MBR slice as a BSD disk, and use BSD disklabels for partitions inside those slices. The disklabel method apparently was too entwined with the kernel. He notes that FreeBSD disambiguated the word partition by calling them slices on MBR systems. Each slice can be thought of as a container to hold BSD partitions, with disklabels identifying the location of the BSD partitions. As is typical throughout the book, Lucas provides the specific commands to complete such tasks such as mbr the disk, create and remove slices, as well as actions involving disklabels.
Chapter 4 covers the Unix File system or UFS. According to Lucas many UFS concepts underlie other file systems and stresses the importance of knowing its basics so you can understand how FreeBSD manages file systems. What I learned is that UFS really consists of two components: the Unix File System, which handles the front-end, user-facing things like permissions, file names, putting files in directories, etc. and the Fast File System (aka FFS) which handles writing files to disk and arranging them for quick access. FFS was written by Kirk McKusick. Now I finally understand Fast File System’s role—it toils in the background while the UFS front-end gets all the attention.
Lucas explains how UFS handles today’s multiple storage options via a storage abstraction layer, vnodes. A vnode is a translation layer between the BSD kernel and the file system on the media you’re using. Lucas says they are never directly manipulated but you’ll encounter them whenever you’re dealing with storage, especially with different file systems. Lucas goes on to explain the various mounting options with UFS. I won’t go into detail because the commands are practically the same as Linux.
What was particularly interesting to me was the ability of UFS to change its behavior based on the fullness of the file system. On a nearly empty file system, it goes for speed. As the file system fills, it shifts to a mode that maximizes space utilization.
Lucas then steps through the process of creating and tuning a UFS file system. And I had no idea that the command background fsck lets FreeBSD perform a file system integrity check on a system running in multi-user mode.
UFS snapshots were covered in this chapter, including the actions to take to create and access snapshots. Again all this information was accompanied with the necessary commands.
Although FreeBSD also supports ZFS, Michael Lucas does not spend much time talking about ZFS. When reading the Afterword (Mat, that is found at the end of the book) I found out why—he plans to publish a book on ZFS and Specialty File Systems in 2015.
Chapter 5 overs File System encryption The first question in this chapter is whether you need encryption. Lucas covers the pros and the cons of disk encryption. And ,yes, there are cons. For example, disk encryption can attract unwanted attention from government agencies.
Lucas mentions that FreeBSD supports several encryption methods but he focuses on the two major ones: GELI and GBDE (GEOM-based Disk Encryption). Each offers its own strengths but Lucas points out that all methods have common factors which he covers first for this topic:
- Cryptographic soundness,
- Encryption performance,
- Cryptographic keys,
- Passphrases, and
- Randomizing encrypted devices.
Chapters 6 and 7 discuss GELI and GBDE respectively. In the interest of time, I won’t go into the details.
Chapter 8 Swap Space – Lucas covers the basics about swap in this chapter including the time honored swap calculation. He also explains how to encrypt your swap space using the available FreeBSD tools.
I was unaware of the fact that you could use a file as swap space, but according to Lucas you can! He says it isn’t ideal but can be useful to bridge temporary situations such as when replacing a failing drive
The standard actions for swap are listed along with an explanation for what it does and why. With FreeBSD 10, the approach for starting a swap file at boot changed. Now there’s an entry in fstab, very similar to how Linux sets it up
Michael W Lucas provides a useful example of how he encrypted his swap space by adding .eli to the end of the device name in his /etc/fstab file. The swapon command/program recognizes this marker and automatically encrypts with a one-time key.
Chapter 9 – GEOM Raid In chapter 1 Lucas introduced us to GEOM (Disk Geometry). In chapter 9 he continues his examination of in terms of hardware versus software RAID. He says all RAID is done in software and what is called hardware RAID is simply RAID being managed by software inside the RAID controller rather than the operating system. Lucas goes on to say that some of these RAID controllers actually run a full FreeBSD operating system with vendor-specific RAID code. If system processor time and memory are at a premium, hardware RAID may be better for you. Hardware RAID is often more simple to manage.
Chapter 9 also includes RAID essentials which, if you’re not familiar with the flavors of RAID, will be very informative. This portion of the chapter went into some detail to describe each RAID version.
For example, there’s really nothing redundant about RAID-0 (striping). Or that RAID0+1 is striping followed by mirroring? Lucas mentions that RAID-5 support, long the industry standard, is not included in the base FreeBSD system but it can be installed from the ports system (sysutils/graid5). However every system upgrade means a rebuild of the graid5 module. Through out the book, Lucas includes these helpful tidbits.
In chapter 9 he takes the time to provide the commands to create, repair, and remove (i.e. destroy) the RAID disks.
Chapter 10 covers SMART or Self-Monitoring Analysis and Reporting Technology let you proactively monitor your hard drives and replace them before they fail…or as Lucas humorously notes: “ it doesn’t guarantee that you’ll get advance notice of failures but it sure beats waiting blindly for the crash.”
Like Linux, FreeBSD uses the smartctl program to query and configure SMART devices, and Lucas helpfully provides the commands to do so, including information on SMART tests because SMART has test routines. Lucas cautions that a proper test would read and write data to every sector but that process would destroy the data already on the drive. Instead, it checks electronics, mechanisms, and ability to read from the disk—all equally important in my opinion. Although Lucas admits it’s a brief introduction, you’ll find it useful, even if you run Linux.
The best is saved for last! It’s chapter 11: Complex Installation. This chapter covers more advanced tasks and, as Lucas states, the strength of FreeBSD’s storage system is not from individual tools but from how you can combine them. In this chapter he sets out to show you. First up: Installing to Gmirror. According to Lucas, you may want to do this if, for example, your computer uses BIOS and you want to use RAID-3, -5 or -10, or other complex RAID protocols. For this method, Lucas describes a workaround for instances where the BIOS can’t find partitions or doesn’t understand FreeBSD’s GEOM classes. The workaround places /boot in a mirrored drive and /, /usr, and the other directories on a RAID-5. He cautions that you have to mirror the disks yourself because the FreeBSD installer won’t do that for you. He then walks you through the process of:
- assigning a partitioning scheme,
- configuring geoms,
- creating the partitions and partition table,
- boot loader,
- file systems, and
- temporary mounts.
I think you get the picture. I didn’t have the time or inclination to attempt this install but he includes everything you need to install via gmirror.
This chapter also includes a section on how to manually install FreeBSD without using the installer. As I read through the steps, I was reminded of my recent review of Awbian when I had to install that Linux distro manually. Lucas also includes information for scripting installations if you prefer to do it that way. Lucas says tat an installation script is a lit of all the commands needed to create your GEOMs and file systems, and extract FreeBSD into them. Conveniently, the author includes a sample install script as well as the link on his site from which you can download the script.
Lucas moves on to full disk encryption and provides the necessary instruction for encryption your computer, although he does say that you can’t completely encrypt everything on a computer.
The final section in this chapter and book discussed expanding virtual disks.
I found this book to be an interesting and informative read and at 9.99, well worth the price of admission.
Michael W. Lucas’ site:
Tilted Windmill Press (Book):
(you also can get it on Amazon but why would you do that when you can get it from him directly?)
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Is it Alive… (or is it a Linux kernel)?
During this segment of the show, I challenge Mat and Tony to identify whether a Linux Distro is alive or dead? Sometimes, I twist the concept for our game show and challenge Mat and Tony to decide if the named entity was a Linux distribution or something else. This week is twist week and I challenge I challenge Mat and Tony to decide whether the named Linux kernel name is real or fake. The items for this week’s show are::
Tony Won By 3!
show (at) smlr.us or 734-258-7009
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