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Tech Tips, Tricks & Trivia

by 'Anil' Radhakrishna
An architect's notes, experiments, discoveries and annotated bookmarks.

Search from over a hundred HOW TO articles, Tips and Tricks

VNet Peering Constraints

Sunday, December 09, 2018
Constraints and what is not possible with VNet Peering:

* Peering virtual networks in different regions is also referred to as global peering. When creating a global peering, the peered virtual networks can exist in any Azure public cloud region, but not in Azure national clouds. You can only peer virtual networks in the same region in national clouds.

* Resources in one virtual network cannot communicate with the front-end IP address of an Azure internal load balancer in a globally peered virtual network. The load balancer and the resources that communicate with it must be in a virtual network in the same region.

* You cannot use remote gateways or allow gateway transit in globally peered virtual networks.

* The virtual networks you peer cannot have overlapping IP address spaces.

* You cannot add address ranges to, or delete address ranges from a virtual network's address space once a virtual network is peered with another virtual network.

* You cannot peer two virtual networks created through the classic deployment model.

* Peerings are not transitive. If you create peerings between: VirtualNetwork1 & VirtualNetwork2
and VirtualNetwork2 & VirtualNetwork3, there is no peering between VirtualNetwork1 and VirtualNetwork3 through VirtualNetwork2.

* You cannot resolve names in peered virtual networks using default Azure name resolution. To resolve names in other virtual networks, you must use Azure DNS for private domains or a custom DNS server.

* There is a nominal charge for ingress and egress traffic that utilizes a virtual network peering.

VNet peering pricing is calculated differently than VNet-to-VNet VPN Gateway pricing.

Source: Official Azure documentation


Interesting & practical innovations in gadgets

Saturday, December 08, 2018
Bold new features that device makers keep coming up with to differentiate from the old & existing -

* Modular smartphone add-ons that bring transformative featuresMoto Mods snap onto any Moto Z phone, transforming it into a device that does things other phones can't like turning it into a projector and photo printer

* Gesture control music, camera, calls with smart band - Fastrack Reflex Wav smart band goes beyond being activity tracker

* Bluetooth enabled stylus as remote for multiple functions - Samsung's S Pen harnesses the power of Bluetooth technology, acting as a remote for Galaxy Note9. Snap photos, change slides, and pause YouTube videos with a press of the button — or set your own custom controls

* EKG/ECG - Heart-rate tracking has always been a big part of the Apple Watch and fitness trackers in general. But until now, it's mainly been used for activity tracking and calorie counting. With the update to Watch OS 5.1.2, heart rate will play a more important role on the Apple Watch as we get access to the two new FDA-cleared features - abnormal heart rhythm alert for all Apple Watches and an electrocardiogram (EKG or ECG) exclusive to the Apple Watch Series 4. Both of which could help warn of potentially life threatening heart conditions - CNET

to be continued....


This Week I Learned - Week #296

Thursday, December 06, 2018
This Week I Learned -

* When you have an asynchronous function, and an Error occurs inside of that function, your script will have continued with the execution already, so there will not be any Error immediately....handling asynchronous functions with callbacks..is not recommended.  A better way of dealing with asynchronity is using promises. Here, in addition to having more readable code, we also have improved error handling - Handling Errors in JavaScript: The Definitive Guide

* ..in the SQL Server documentation Microsoft notes that you should not enable any caching on disks that are dedicated to log files because it could result in a minor decrease in disk performance.

* Azure Site Recovery charges include Network egress costs to replicate data changes from the source VM disks to another Azure region. Azure Site Recovery uses built-in compression to reduce the data transfer requirements by approximately 50%.

Microsoft Azure Site Recovery (ASR) now supports SUSE Linux Enterprise Server 11 SP3/SP4 and SUSE Linux Enterprise Server 12 SP1/SP2/SP3

* Availability Zones are especially useful if your customers are concentrated in a single region & you must obey regulatory requirements and laws that require your data/services to be highly available inside a single Azure Region.

* Azure region is defined by a bandwidth and latency envelope. Typically they are hundreds of miles apart with < 2ms latency diameter (round trip). Customers see regions, not DCs

* VNETs and Subnets can cross AZ. Availability Sets cannot span regions.

The virtual network spanning the Availability zones, and any traffic traveling between the zones will be charged for at the normal VNet Peering rate within a region

Availability Zones and Availability Sets cannot be used together: when creating a Virtual Machine (VM), you will have to specify an AS, or AZ assignment, you cannot do both.

* The Basic tier load balancer is restricted to non-availability zone deployments.

* A "R" in the name of a Azure VM type indicates an additional Remote Direct Memory Access (RDMA) NIC is added to the virtual machine, offering high bandwidth, low latency, and low CPU impact data transfers just like "S" indicates that the virtual machine supports Premium Storage (SSD) as well as Standard Storage (HDD – the normal storage used).

* You can aggregate Standard Storage data disks to get more IOPS in Azure.

* Most virtual machines use host-based flash storage for the temp drive; this offers high IOPS and by being in the host it offers the lowest possible latency. You might have some benefits by moving the SQL Server TempDB to the temp drive.

When using virtual network peering, the virtual networks can be in the same, or different, supported Azure regions. The virtual networks can be in the same or different Azure subscriptions (even subscriptions belonging to different Azure Active Directory tenants).

The Contoso Azure Migration article series provides information and scenarios that illustrate how to set up a migration of infrastructure, and run different types of migrations. 

* Because most last names can be spelled in a variety of ways, Soundex allows people to search for ancestors across differently spelled surnames. Soundex is a phonetic algorithm for indexing names by sound, as pronounced in English.

Jeff Bezos turned an internal initiative into Amazon Web Services, a subsidiary that does more than $24 billion in annual revenue.

* Only female mosquitoes bite and feed on the blood of humans or warm-blooded animals. If a mosquito finds enough victims to bite and avoids being squashed, it can live as long as three weeks. During that time, it may lay up to five clutches of more than 100 eggs each.

* Mosquitoes are highly sensitive to smell — they can usually sniff though your perfumes and lotions. Mosquitoes look for plumes of carbon dioxide, which we humans create when we exhale. And they'll start moving toward those plumes - NPR

Apart from carbon dioxide, there are a number of other chemicals — including octenol, lactic acid, acetone, and estradiol — that are naturally emitted by our bodies and further attract mosquitoes when blended with carbon dioxide.

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This Week I Learned - Week #295

Saturday, December 01, 2018
This Week I Learned -

Sites like Google Sheets ship up to 5.8MB of script (when decompressed)

* ...roughly 80% of all enterprise applications run on Windows Server. Of those applications, 70% still run on Windows Server 2008 or earlier versions....By containerizing legacy applications and their dependencies with the Docker Enterprise container platform, they can be moved to Windows Server 2016 and later OS without code changes.... And because containerized applications run independently of the underlying operating system, they break the cycle of extensive, dependency ridden upgrades, creating a future-proof architecture that makes it easy to always stay current on the latest OS. Docker Enterprise allows you to upgrade Windows Server applications to a cloud portable architecture without recoding. And only Docker can run Windows Server containers - Docker Blog

* You can run any application in Docker as long as it can be installed and executed unattended, and the base operating system supports the app.

* The Pluralsight course Modernizing. NET Framework Apps with Docker shows how you can take existing. NET applications, apps that may be 6 months old or 10 years old, package them to run in containers on Windows, and then use the Docker platform to modernize the application.

* Whether you work with Jenkins, Azure DevOps Services, Visual Studio Team Foundation Server, Atlassian, or other services, this guide - Enterprise Cloud Control Plane Planning [PDF], can help you automate beyond the CI/CD pipeline to the management and policy layers - AzureCAT Guidance

* ...the cloud can be a great asset for backups and DR but before jumping in its important to be aware of the details that you need to know for a successful implementation. First, backing up to the cloud means that you are no longer in control of the backup media. Instead, the control over your backups is in the hands of your cloud provider. Next, cloud backups have the potential to increase your backup window. Backing up to the cloud means the backup data has to be transferred across the Internet which means that there can be both security and latency issues. The backup data itself needs to be encrypted as it is transferred to the cloud to prevent any unauthorized access. Backup and restore times to the cloud are also impacted by network latency which can extend your Recovery Time Objectives (RTOs). To offset the network latency issue, some backup products offer features like data compression, deduplication and WAN acceleration that can vastly reduce the amount of data transferred across the Internet and speed up the backup process. One way many businesses have dealt with this problem is by having staged backups where an initial backup happens locally and then a later process copies that backup to the cloud - Petri

* AWS Outposts is an on-premises, private cloud service with hardware and software solution that runs either AWS native stack or VWware cloud on AWS stack.

* So far the civilian use of drones was unregulated in India but from December 1 you will have to follow a set of new rules and regulations issued by the Directorate General of Civil Aviation (DGCA) under which you may even be required to take a licence and get your drone registered with the government - Mint

Every Indian state has its own governing strategy preferences. In some states, groups of districts are categorized under one or more divisions.

* The Indian Government is divided into Levels, according to the 7th Central Pay Commission. There are totally 18 levels, with 03 entry points:
- Level 01 - 05 - Lower Services - Peons, Constables, Stenos, Clerks etc.
- Level 06 - 09 - Middle Services - Inspectors, Section Officers, DSPs, Block Officers etc.
- Level 10 - 18 - Upper Services - IAS, IPS, IRS, Undersecretary etc.

* In a single Iphone there is about 75 elements : two-thirds of the periodic table

* Roughly half of the world’s bird species migrate. The bright lights of cities can be particularly disorienting to migrant birds, many of which fly at night, resulting in fatal collisions with buildings and radio towers

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This Week I Learned - Week #294

Sunday, November 25, 2018
This Week I Learned -

Azure DevOps offers 99.9 percent SLA and new features every three weeks.

* When you're migrating from an On-premises world, you use the physical cores which have hyper threading. In GCP we call these vCPUs or virtual CPUs. A vCPU is equivalent to one hyper threaded core. Therefore, if you have a single core hyper threaded CPU On-premises that would essentially be two virtual CPUs to one physical core. So, always keep that in mind as oftentimes, people will immediately do a test. They'll say, "I have a four core physical machine and I'm going to run four cores in the Cloud." And ask why their performance isn't the same - Essential Cloud Infrastructure: Foundation, Coursera

* Created at Netflix, Spinnaker is an open source, multi-cloud continuous delivery platform for releasing software changes with high velocity.

* Use Google Cloud Memorystore to build application caches that provides sub-millisecond data access. Cloud Memorystore is compatible with the Redis protocol, allowing easy migration with zero code changes.

* Your data stored in Google Archival Cloud Storage - Nearline and Coldline is available to you in sub-second average response times, rather than in hours or days.

The most common protocols for exporting file shares are Network File System (NFS) for Linux and the Common Internet File System (CIFS) for Windows.

* GCP Custom VM types allow you to allocate up to 624 GB of memory and up to 96 cores per machine.

Amazon EC2 Instance Store provides temporary block-level storage for your instance. This storage is located on disks that are physically attached to the host computer. An instance store consists of one or more instance store volumes exposed as block devices.

* GCP Local SSDs have an even higher throughput and lower latency than SSD persistent disks because they're attached to the physical hardware.

* The official set of icons to build architectural diagrams of Google Cloud Platform are available at cloud.google.com/icons/

Fitbit has a female health tracking feature

* India now has more users of Whatsapp (over 200 million, or one in six Indians) than any other country

* If mangoes have been naturally ripened, the smell should be apparent from at least four meters away...the proper way to handle the prized Alphonso variety - “They are just like eggs: if they bang a little, they rot.”

* “You only have power over people as long as you don't take everything away from them. But when you've robbed a man of everything, he's no longer in your power—he's free again.” ― Alexander Solzhenitsyn

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