Saturday, July 26, 2014

Asus 6 Series Wireless Routers - FINALLY an AP with Decent Strength / Coverage for Home / SMB


Sorry for being a slack-ass.

Rather than have a fluffy write-up of the unit, I've now actually got one in my hot little hands (my old-trusty Netgear WNDR3700 decided to pack it in after four years).

Although the reviews on SmallNetBuilder are good and I love the work they do, their theory could go a little way further.

I'm currently working on a wireless article that brings together the theory of wireless plus how this applies in the real world, and all the factors that you should bring into the equation when talking wireless (and uplinks as well!).

In the mean time, don't bother buying anything else except an Asus RT-N66U or one of it's 802.11ac variants.


In the enterprise environment it's pretty much taken for granted that wireless AP's will throw wireless signal a decent distance (generally about 15M in a spherical pattern with the AP in the middle) and handle up to about 20 clients when using factory internal antennas.

In the situation where I need to throw signal further than that of a factory internal antenna, I employ an AP with external antenna connectors and then model the RF coverage based on an appropriate external antenna to ensure the required coverage is delivered.

Home AP's (generally sold as wireless routers) always seem to have the same if not better wireless throughput and routing performance than enterprise APs (at short range) but always skimp out on the antennas and internal amplifiers resulting in piss poor coverage and in-turn poor throughput within the home (unless you're generally within 10m of the AP).

Thankfully, that has now changed.

The following models of Asus Wireless Routers have the same if not better processors and 2.4/5GHz radios than their enterprise counterparts and also pack 2.4GHz and 5GHz amplifiers and use external antennas (reportedly 5dBi gain).

RT-N66U (802.11n Simultaneous Dual-Band)
RT-AC66U (802.11AC 1750)
RT-AC68U (802.11AC 1900)

The signal transmit power is significantly better and receive sensitivity also much better than a standard SOHO AP.

In the real world, this means that high throughput applications such as playing a video file off another device on the same WLAN will have much better performance within the same environment when compared to a standard SOHO AP.

As a quick overview, the specs of these AP's is as follows:

The System On a Chip (SoC) processors used in these APs provide fantastic routing performance between interfaces within the device (i.e. Gigabit LAN and 2.4GHz / 5GHz radios)  and the Broadcom chips used for both the 2.4GHz and 5GHz radios are generally regarded as some of the best in the industry.

RF Coverage Pattern (Antenna Modelling):

Example of coverage and throughput provided in a house:

In the event that you require more coverage than what is provided by the included external antennas, using the Asus 6 series you have the option of purchasing additional external antennas to throw the signal even further.

Friday, July 11, 2014

CentOS 7 Released

New version available.
Apparently adds some things that were unique to Fedora up until now.

Sunday, July 6, 2014

The state of Hypervisor Virtualisation 2014

I wish someone would just make the perfect hypervisor.

Basically I guess what I'm asking for is ESX and VCenter to be released as Open Source products and the file system changed to EXT4.

I guess I need to provide some background to that statement...

I recently had a disk drop out of my home ESXi server with nothing particularly important on it but just for curiosities sake I thought I'd see what's involved in restoring a VMFS partition (more specifically, a VMFS5 partition).

Let me sum this up for you: good f#$%ing luck.

While NTFS and EXT3 have many good recovery tools available, there are basically two for VMFS:

PartedUtil and vmfs-tools for Linux.

PartedUtil sucks. Sorry, there's just nothing else to say about that application.

vmfs-tools (a VMFS5 enhanced version of the Google open source VMFS3 driver) is somewhat better but is still a very basic tool for something that a Windows or Linux application would barely break a sweat to achieve the same thing.

I started talking about VMFS with some of the more knowledgeable server engineers I work with who advised that "now that I mention it" they seemed to also think that disks may very well die faster in VMWare environments.

Obviously in an enterprise environment you will be running your disks in enterprise grade SANs so in the event of a disk failure it's a simple swap out / swap in and add to the array but it did seem very odd that disks failed faster when acting as targets for a VMWare environment.

Conspiracies aside, I've developed gripes relating to the changes that occur between different versions of ESX.

Finally, license costs.
Oh the license costs.

In a world where Xen, Hyper-V and KVM are taking off, VMWare licensing costs should only be going in one direction.

So, as I need to be across all things hypervisor in my job, I thought I'd run up Xen (and in time KVM) to see what it's like at this point in time (as I remember about two years ago Xen was incapable of CPU resource reservation).

In recent times, Citrix has relinquished Xen to being an Open Source product once again (which means it has now gone full circle) 

There are two options for running a Xen hypervisor at this point in time.

The first is to used the last cut as released by Citrix which is at least stable with a good interface.

The second is to install XenServer on top of a Linux distro of your choice.

This is quite a new option and not one that I have time to play with right now.

On a sidenote, Amazon Web Services apparently run their own custom cut XenServer environment.

I don't know if that's a good or a bad thing.

Anyway, I fired up the latest Citrix rolled up version of Xen (6.2) and not much has changed.

It still can't do CPU resource reservation (high medium low is not reservation) and the drivers for DVD / BD drive emulation still don't work properly for Windows guests.

These are the exact same problems I had two years ago. Fail.

Oh - and the recently released CentOS 7 doesn't boot after install.

There are two potential issues I see with Xen.

First: How much has Citrix mucked with Xen and are these changes actually for the good of the product?

Second: Now that it has been re-released into the Open Source domain, the dev community has to scramble to work with an inherited codebase.

The code might not actually be what devs want to work with (as in they might disagree with the way some elements of the app are built) and given that the code is so established, that could be a problem. 

This might result in a slowed development cycle and lack of community support.

So, back to ESXi for me for the time being.

Hopefully KVM has more to offer...