Extended Long Term Support for Debian
Freexian extends security support for old Debian releases up to 10 years, albeit only on the subset of packages used by the customers of this service. Click here to learn more.

With the introduction of SAS 12Gbps, seems like "it's time" to do a braindump on SAS.

Work in progress, as usual.

History

By the late '90's, SCSI and PATA were the dominant technologies to attach disks. Both were parallel bus multiple drop topologies and this kind of sucked. SATA and Serial Attached SCSI (SAS) evolved from those, using a serial bus and hub-and-spoke design.

Early SATA/150 and SATA/300 were a bit rough and had some issues, as did SAS 3Gbps. You probably want to avoid older controllers, cabling, expanders, etc. that doesn't support 6Gbps because some of it has "gotchas" in it. In particular a lot of it has 2TB size limitations. Most 3Gbps hard drives are fine though.

Similarities, Differences, Interoperability

SAS and SATA operate at the same link speeds and use similar cabling. SAS normally operates at a higher voltage than SATA and can run over longer cabling.

SAS and SATA use different connectors on the drive. The SATA drive connector has a gap between the signal and power sections, which allows separate power and data cables to be easily connected. The SAS drive connector does not have a gap, and instead has a second set of pins on top. This second set of pins is the second (redundant) SAS port. There are pictures of the top and the bottom of the drive connector.

SATA drives can be attached to a SAS port. Electrically, the SAS port is designed to allow attachment of a SATA drive, and will automatically run at SATA-appropriate voltages. Physically, the SAS backplane connector has an area that will allow either the gapless SAS or the gapped SATA connector to fit. See picture of SAS backplane socket.

SAS drives are incompatible with SATA ports, however, and a SATA connector will not attach to an SAS drive. Don't try. The gap is there to block a SAS drive from being connected to typical SATA cabling, or to a SATA backplane socket.

When a SATA drive is attached to a SAS port, it is operated in a special mode using the Serial ATA Tunneling Protocol (STP).

If you’ve spent any time around UNIX, you’ve no doubt learned to use and appreciate cron, the ubiquitous job scheduler that comes with almost every version of UNIX that exists. Cron is simple and easy to use, and most important, it just works. It sure beats having to remember to run your backups by hand, for example.

But cron does have its limits. Today’s enterprises are larger, more interdependent, and more interconnected than ever before, and cron just hasn’t kept up. These days, virtual servers can spring into existence on demand. There are accounting jobs that have to run after billing jobs have completed, but before the backups run.

Author : Sol Lederman

What Is a Container and How Are Containers Used? A starting point for an exploration of containers and how they’re used is this simple definition: a container is a packaging format for a unit of software that ships together.

A container is a format that encapsulates a set of software and its dependencies, the minimal set of runtime resources the software needs to do its function. A container is a form of virtualization that is similar to a virtual machine (VM) in some ways and different in others. VMs encapsulate functionality in the form of the application platform and its dependencies. The key difference between VMs and containers is that each VM has its own full-sized OS, while containers typically have a more minimal OS.

Author : Greg Bledsoe

“If you build it they will come.” Are freeways built to travel between existing communities, or do communities spring up around freeways? Is this a chicken-and-egg problem, or is there a complex interaction where such things shape each other?

The use of UNIX and Linux security tools raises similar questions. Do people work the way they do because of the tools they have, or do people have the tools they have because of the way they work?

Author: Kyle Rankin

This book explores system administrator fundamentals. These days, DevOps has made even the job title “system administrator” seem a bit archaic, much like the “systems analyst” title it replaced. These DevOps positions are rather different from typical sysadmin jobs in the past in that they have a much larger emphasis on software development far beyond basic shell scripting. As a result, they often are filled with people with software development backgrounds without much prior sys- admin experience. In the past, sysadmins would enter the role at a junior level and be mentored by a senior sysadmin on the team, but in many cases currently, companies go quite a while with cloud outsourcing before their first DevOps hire. As a result, DevOps engineers might be thrust into the role at a junior level with no mentor around apart from search engines and Stack Overflow posts. In this book, I expound on some of the lessons I’ve learned through the years that might be obvious to longtime sysadmins but may be news to someone just coming into this position.

Download PDF

Free server control panel

FASTPANEL is comfortable, functional and modern.
Managing a server has never been easier!

1) An HBA is a Host Bus Adapter.

This is a controller that allows SAS and SATA devices to be attached to, and communicate directly with, a server. RAID controllers typically aggregate several disks into a Virtual Disk abstraction of some sort, and even in "JBOD" or "HBA mode" generally hide the physical device. If you cannot see the type of device (such as "ST6000DX000-1H217Z" in "camcontrol devlist", you DO NOT HAVE A TRUE HBA. If you cannot get the output of "smartctl" for a device, you DO NOT HAVE A TRUE HBA. A true HBA passes communications through itself directly to a drive without further processing. No amount of marketing department wishful thinking can change that technical reality.

2) FreeBSD has incredibly robust support for the LSI HBA's.

FreeBSD's LSI HBA (mps/mpr) drivers are authored by LSI and carefully designed to work with their HBA firmware. The FreeNAS userbase has installed many thousands of these cards which have, in aggregate, BILLIONS of problem-free run-hours. Not only are they known to work very well during normal operations, but they're also known to work correctly during ABNORMAL operations, such as when a disk times out or throws an error. SMART is properly supported. Forum members are incredibly familiar with all the variations on these and can provide useful assistance. Cards such as the LSI 9240-8i, IBM ServeRAID M1015, Dell PERC H200 and H310, and others are readily available on the used market and can be converted to LSI 9211-8i equivalents.

3) You must crossflash to IT/IR firmware

If you don't crossflash, then a lot of the remainder of this ALSO applies to LSI non-IT-20.00.07.00 HBA's!! The IR firmware is also fine but is a few percent slower. It is not clear there is any value to doing this as you would never want to use an IR virtual device with FreeNAS. We used to do this in the old days for boot devices, but with ZFS boot this is probably no longer relevant.

The LSI 9240 (etc) default MFI firmware is apparently being sold on eBay as "IR" by clueless sellers. The MFI firmware is unsuitable for FreeNAS and may cause your pool to get eaten.

The LSI 9211-8i (PCIe 2.0 based on LSI 6Gbps SAS2008) and LSI 9207-8i (PCIe 3.0 based on LSI 6Gbps SAS2308) both require firmware 20.00.07.00.

TrueNAS is not as simple as videos make it look, though it is fairly easy to get a system running if you read the documentation and don't color outside the lines.

If you want to save yourself lots of money and loads of time, the top of the page has Documentation and Resources tabs which contain extremely helpful information like the TrueNAS manuals. There's also a Search tool at the upper-right that works extremely well. If you understand the system and requirements before jumping in you'll save money, time, and frustration.

As general advice, if you run TrueNAS as a NAS and don't add things to it it tends to run fine and without issue, though I suggest using an Uninterruptible Power Supply and NUT.

You’ve probably heard talk about how building servers is outdated, inefficient, or even downright dangerous.

Virtualized, containerized, and serverless solutions definitely provide some benefits over legacy, server-based architecture. And there are many times where these solutions are truly ideal for delivering modern applications.

But at the end of the day, all of these containerized solutions are simply tools, VMs, or applications running on someone else’s server. Managed solutions can be a fantastic relief, but they can also be a major source of frustration since you’re removed from the inner workings of the platform.

There are many times where it’s beneficial – or even imperative – to operate your own server. For instance, if you’re running a home NAS, or if you have special hosting needs.

Building, operating, and maintaining your own server is a great way to improve your sysadmin skills and to learn deep, nuanced aspects of the systems you work with. //

The experiences I have had over the years have shaped me and given me different and unique perspectives, to the point where I’ve made a concerted effort to move away from Linux and towards FreeBSD for all of my production work. //

If you’re going to build your own servers, be a good steward. Take some steps to do it in a smart way:

• Write thorough documentation. Taking good notes not only reinforces your present learnings but helps your future self remember details about actions from the past.

Deploy our best deals yet on KVM VPS in 7 different locations, instantly set up! CentOS, Rocky Linux, AlmaLinux, Fedora, Debian and Ubuntu Supported. Custom ISO's can also be mounted via support ticket.

GameServer is a TurnKey GNU/Linux appliance for hosting game servers on Linux. It provides a way of deploying game servers in minutes in cloud environments or local VMs.

Automatic installation of gameservers using LinuxGSM. - GitHub - jesinmat/linux-gameservers:

Tool for automatic installation of game servers. Wrapper for LinuxGSM.

Manage Your Game Server Easily With LinuxGSM

The command-line tool for quick, simple deployment and management of Linux dedicated game servers.