VIRTUAL PRIVATE SOMETHING

I was fairly late to start playing with VPSs, though it seems I 
started at a good time a few years ago because the similarly-priced 
(ie. extremely cheap ~$1AUD/month) KVM VPS plans now mostly have 
more limited specs. This has kept me with 1GB of RAM and 16GB 
storage through a VPS offer which was downgraded just months after 
I signed up for it it. What hasn't stayed with me is the one 'vCPU'.

Of course I still get a virtual CPU to do the work, but it's not 
the one that I started with. Earlier this year the host advised of 
a hardware issue with the RAID array of the physical server it was 
running on, and as such they moved all users over to another 
physical server. Actually they just made me a second VPS account 
and left me a week to move things over myself before disabling the 
old one, which did at least provide a handy opportunity to convert 
the original host-provided Debian installation over to blissfully 
Systemd-free Devuan and do a version upgrade, while the old server 
was still running to host my websites.

But although the 'new' VPS had the same RAM and SSD storage, my 
vCPU had changed:

Old:
	model name      : Intel(R) Xeon(R) CPU E5-2690 0 @ 2.90GHz
	stepping        : 7
	microcode       : 0x1
	cpu MHz         : 2899.998
New:
	model name      : Intel(R) Xeon(R) CPU E5-2695 v2 @ 2.40GHz
	stepping        : 4
	microcode       : 0x42e
	cpu MHz         : 2399.998

Still an old model Xeon processor, but a slower clock speed! Sure 
enough, tests showed a corresponding reduction in processing speed 
for one of my common CPU-bound processing tasks. So there goes my 
assumption that the same VPS deal will get you the same or better 
CPU performance forever, even if the advertised stats stay the same.

But at least the CPU stats have some relation to real performance 
with that provider, I've found that the free VPSs that Oracle Cloud 
offers are over-provisioned, so when you turn up the CPU load and 
watch in Top, the hyperviser constantly steals a big chunk of 
processing time away, making their 'oCPU' stats potentially 
meaningless since you're not actually getting all of those CPUs to 
yourself.

The other thing that happend with the move to the replacement VPS 
was that the IP address changed, for the third time (last time 
there wasn't even a transition period, I had to rush to reconfigure 
my dead domains after getting the email). Also to again ask support 
to also set its rDNS setting to the main domain name for the sake 
of email (not possible in the 'control panel', contrary to their 
documentaiton when I first signed up). Unfortunately this most 
recent IP address, although fine by public blacklist checks, seems 
to have been blacklisted by various big email hosts including 
Microsoft, Apple, and AOL. So in spite of ticking all the boxes for 
DKIM, SPF, DMARC, and rDNS, they suddenly started rejecting my 
email outright. Microsoft (most important of the three due to all 
the Hotmail addresses they control) annoyed me particularly because 
the server rejection message didn't explain how to request removal 
from the blacklist, so I had to find instructions here:

https://www.rackaid.com/blog/hotmail-blacklist-removal/

Then that required me to create a Microsoft account just to fill in 
their blacklist removal form!

So the take away from my VPS experience so far has been that if you 
want a predictable environment (especially to run a mail server) 
you need to ditch the virtual, run on dedicated server hardware, 
and buy your own IPv4 address/block to boot! So, as is to be 
expected, it's all so much easier if you have money to burn. It's 
just annoying that you have to experience these services yourself 
to find out how they really work.

 - The Free Thinker