Web Excursions 2022-05-17
Heroku still works, but it's obviously been in maintenance mode for years.
[Inside Heroku,] there was a goal that just kind of grew in scope over and over without reaching an end state: the Dogwood stack.
In Heroku each "stack" is the substrate the dynos run on.
It encompasses the AWS runtime, the HTTP router, the logging pipeline and a bunch of the other infrastructure like the slug builder and the deployment infrastructure.
The three stacks Heroku has used are named after trees: Aspen, Bamboo and Cedar.
Every Heroku app today runs on the Cedar stack, and compared to Bamboo it was a generational leap in capability.
Cedar was what introduced buildpacks and support for any language under the sun.
Prior stacks railroaded you into Ruby on Rails (Heroku used to be a web IDE for making Rails apps).
However there were always plans to improve with another generational leap.
This ended up being called the "Dogwood stack", but Dogwood never totally materialized
because it was too ambitious for Heroku to handle post-acquisition.
Parts of Dogwood's roadmap ended up being used in the implementation of Private Spaces,
but as a whole I don't expect Dogwood to materialize in Heroku in the way we all had hoped.
However, I can confidently say that fly.io seems like a viable inheritor of the mantle of responsibility that Heroku has left into the hands of the cloud.
for context each dyno has a mutable filesystem.
However that filesystem gets blown away every time a dyno reboots.
Having something that is mutable and persistent is mind-blowing.
Being the more modern file system, APFS has many features that HFS+ lacks. Among these are
sharing of free space between volumes inside the same container/partition,
improved reliability thanks to copy-on-write, and
special file types such as clones and sparse files.
The only significant feature of HFS+ lacking in APFS is support for directory hard links,
but they are seldom used outside Time Machine backups, and
Time Machine now backs up to APFS volumes using a better method in any case.
The most compelling argument for retaining HFS+ is on rotating hard disks,
because APFS can result in severe fragmentation, most importantly in the file system metadata,
so causing degraded performance
one basic question is whether there is any difference in performance between the file systems to begin with.
When tested with initially empty file systems, there is no evidence of any inherent difference in read or write rates for hard disks formatted in HFS+ or APFS.
As a disk fills with files and their data, their performance is expected to fall faster when using APFS.
APFS may thus remain acceptable for use for more static storage on rotating hard disks.
Differences in write performance on SSDs don’t appear significant.
HFS+ should only be considered for retention as the format of active working hard disks, where APFS features aren’t required.
For all other storage, APFS should be preferred.
Boot disks are now required to use APFS.
Although it’s possible to install and boot Monterey from a hard disk,
it’s not recommended except in an emergency because of the marked performance penalty.