This Week I Learned - Week #296
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.
* 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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