Some of the most glaring omissions from Lightsail are scheduled tasks or triggers – which would provide the ability to automate backups. Competitors in this space like DigitalOcean are all set, as they offer a backup option, whereas for AWS I’m assuming they hope you’ll shift over to EC2 as fast as possible to get the extra bells and whistles.
I have one Lightsail server that’s been running for 6 months now, and it’s all been rosy. Except – I had been using a combination of first AWS-CLI automated backups (which wasn’t ideal as it needed a machine to run them), and then some GUI automation via Skeddly. However – while Skeddly works just fine, I’d rather DIY this problem using Lambda and keep everything in cloud native functions.
This post details my switch over to using Powershell and Cloudflare to update a DNS record to a server’s current IP. This effectively emulates dyndns for this host – except it’s free.
There are a load of other options out there, which even include some simple-but-quite-clunky apps for domain registrars like NameCheap; but installing third party software is not the route I want to take.
I previously had my target domain (let’s call it targetdomain.com) hosted on a Linux box, and used SSH to update the DNS settings via a Windows server. This worked well for three years without a blip – but was clunky. I was using a scheduled task to start a bat file, which then ran Putty to run the shell script…to update a config on a server which was only hosting the domain to serve this purpose.
I’ve been using Cloudflare for years, and set aside time to write a script to use their service for this purpose. As it turns out, people have done this for years – so I’ve taken one off the shelf.
Amazon Web Services (AWS) offers some very affordable archive storage via it’s S3 Glacier service. I’ve used this on a backup account in the past to store archives, and have decided it’s time to clear down this account (oh, and save $0.32 a month in doing so).
The main challenge with doing this, is that unlike S3, S3 Glacier (objects stored directly there rather than using the Glacier storage tier within S3) objects can only be deleted via the AWS CLI. And to delete a Glacier Vault, you’ve got to delete all of the objects.
In this post I’ll spin up a Lightsail box and wipe out the pesky Glacier objects through the AWS CLI. This doesn’t require any changes on your local PC, but will require some patience.
There’s often a discussion about what each of these autonumber/hash functions does in Qlik. We commonly see these functions used for creating integer key fields, anonymising data (for example, names in demo apps), and maintaining long string fields for later comparison (as the hashes are shorter than the strings they replace).
To do this, I’m using the script below. I’m also keen to show outputs from QlikView vs Qlik Sense, and results of running the same script on another machine.
My observations are the following:
– AutoNumber/AutoNumberHash128/256 – different output per load as the value is typically based on the load order of the source data
– Hash128/160/256 – the same output, across every load. Stays the same between Qlik Sense and QlikView, and also between different machines
I recently spotted an unexpected slow-down in a load script, which was caused by using one of these functions. In summary:
– Using RowNo() in a simple load script is considerably slower than RecNo()
– If you must use RecNo(), it may be faster to do this in a direct load
– If you must use RowNo(), it may be faster to do this in a resident load
If you’ve got a couple of VMs, then trimming them occasionally will help with storage management on the host. Disk files (like VDI and VMDK images) will grow over time if the VM was configured to expand the disk as needed – but they will never shrink on their own.
This was tested on a Windows 10 VM managed by VirtualBox, the starting file size was over 40GB, as it had been used for various roles and grown over time.
In this post I explore the outputs of RecNo() and RowNo() to demonstrate the difference visually.
These two fields are often used interchangeably, but they provide different output. In summary:
– RecNo() is a record number based on source table(s)
– RowNo() is a record number based on the resulting table
As a result, RowNo will always provide a unique integer per row in an output table, while RecNo is only guaranteed to be unique when a single source is loaded (RecNo is based on each single source table, interpreted individually rather than collectively).