mirror of
https://github.com/schoebel/mars
synced 2025-02-24 08:37:28 +00:00
doc: improve concept of "scalability"
This commit is contained in:
Thomas Schoebel-Theuer
parent
c8e6f17292
commit
eda58110a4
@ -187,6 +187,7 @@ reference "chap:GNU-FDL"
|
||||
\end_layout
|
||||
|
||||
\begin_layout New Color Box Type
|
||||
|
||||
\begin_inset Argument 2
|
||||
status open
|
||||
|
||||
@ -235,6 +236,7 @@ thetcbcounter : #1
|
||||
\end_layout
|
||||
|
||||
\begin_layout New Color Box Type
|
||||
|
||||
\begin_inset Argument 2
|
||||
status open
|
||||
|
||||
@ -283,6 +285,7 @@ thetcbcounter : #1
|
||||
\end_layout
|
||||
|
||||
\begin_layout New Color Box Type
|
||||
|
||||
\begin_inset Argument 2
|
||||
status open
|
||||
|
||||
@ -331,6 +334,7 @@ thetcbcounter : #1
|
||||
\end_layout
|
||||
|
||||
\begin_layout New Color Box Type
|
||||
|
||||
\begin_inset Argument 2
|
||||
status open
|
||||
|
||||
@ -4743,6 +4747,17 @@ reaction time
|
||||
in units of milliseconds.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Paragraph*
|
||||
Requirements vs Solutions
|
||||
\begin_inset CommandInset label
|
||||
LatexCommand label
|
||||
name "par:Requirements-vs-Solutions"
|
||||
|
||||
\end_inset
|
||||
|
||||
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
\noindent
|
||||
\begin_inset Graphics
|
||||
@ -5851,6 +5866,26 @@ name "sec:What-is-Scalability"
|
||||
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
The term
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
is
|
||||
\series bold
|
||||
\emph on
|
||||
dangerous
|
||||
\emph default
|
||||
for your business
|
||||
\series default
|
||||
.
|
||||
Why?
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
Many technical people know that
|
||||
\emph on
|
||||
@ -5859,7 +5894,7 @@ tightly coupled
|
||||
computers like SMP = Symmetric Multi Processing systems or NUMA = Non-Uniform
|
||||
Memory Access systems have some
|
||||
\series bold
|
||||
scalabily limit
|
||||
scalability limit
|
||||
\series default
|
||||
, also called
|
||||
\emph on
|
||||
@ -5997,6 +6032,243 @@ much more expensive
|
||||
as further contributors to TCO = Total Cost of Ownership.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
\begin_inset VSpace defskip
|
||||
\end_inset
|
||||
|
||||
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
\noindent
|
||||
\begin_inset Flex Custom Color Box 2
|
||||
status open
|
||||
|
||||
\begin_layout Plain Layout
|
||||
\begin_inset Argument 1
|
||||
status open
|
||||
|
||||
\begin_layout Plain Layout
|
||||
|
||||
\series bold
|
||||
Horizontal vs Vertical Scaling, alias scale-out vs scale-up
|
||||
\end_layout
|
||||
|
||||
\end_inset
|
||||
|
||||
Some presentations are arguing with questionable claims about
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
horizontal scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
|
||||
\begin_inset Formula $\cong$
|
||||
\end_inset
|
||||
|
||||
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
scale-out
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
vs
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
vertical scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
|
||||
\begin_inset Formula $\cong$
|
||||
\end_inset
|
||||
|
||||
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
scale-up
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
.
|
||||
These compound notions belong to a
|
||||
\emph on
|
||||
taxonomy
|
||||
\emph default
|
||||
.
|
||||
Their origin is from
|
||||
\emph on
|
||||
scaling methods
|
||||
\emph default
|
||||
, which is not the same as
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
(notice the grammatical suffixes -ing vs -ability).
|
||||
A rough explanation can be found in
|
||||
\begin_inset Flex URL
|
||||
status open
|
||||
|
||||
\begin_layout Plain Layout
|
||||
|
||||
https://en.wikipedia.org/wiki/Scalability#Horizontal_(scale_out)_and_vertical_scal
|
||||
ing_(scale_up)
|
||||
\end_layout
|
||||
|
||||
\end_inset
|
||||
|
||||
(retrieved in Feb 2022).
|
||||
Essentially, these notions refer to
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
loosely coupled
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
vs
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
tightly coupled
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
, and thus they belong to the
|
||||
\series bold
|
||||
solution space
|
||||
\series default
|
||||
,
|
||||
\emph on
|
||||
not
|
||||
\emph default
|
||||
to requirements.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Plain Layout
|
||||
\noindent
|
||||
\begin_inset Graphics
|
||||
filename images/MatieresCorrosives.png
|
||||
lyxscale 50
|
||||
scale 17
|
||||
|
||||
\end_inset
|
||||
|
||||
As explained in paragraph
|
||||
\begin_inset CommandInset ref
|
||||
LatexCommand nameref
|
||||
reference "par:Requirements-vs-Solutions"
|
||||
plural "false"
|
||||
caps "false"
|
||||
noprefix "false"
|
||||
|
||||
\end_inset
|
||||
|
||||
and several sections like
|
||||
\begin_inset CommandInset ref
|
||||
LatexCommand nameref
|
||||
reference "sec:Requirements-for-Geo-Redundancy"
|
||||
plural "false"
|
||||
caps "false"
|
||||
noprefix "false"
|
||||
|
||||
\end_inset
|
||||
|
||||
, mix-up of requirements with solutions can have
|
||||
\series bold
|
||||
adverse effects
|
||||
\series default
|
||||
.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Plain Layout
|
||||
\begin_inset Graphics
|
||||
filename images/lightbulb_brightlit_benj_.png
|
||||
lyxscale 9
|
||||
scale 5
|
||||
|
||||
\end_inset
|
||||
|
||||
In practice, scale-up by addition of
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
more disks
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
or
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
more RAM
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
or
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
more CPUs
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
depends on the already deployed hardware.
|
||||
HDD or SSD addition is possible during operations, provided you have bought
|
||||
some enclosures with hot-swappable free slots.
|
||||
RAM or CPU power requires more preparations.
|
||||
While Intel- oder AMD-based standard servers are inducing an effort similar
|
||||
to a repair, there exists
|
||||
\emph on
|
||||
specialized hardware
|
||||
\emph default
|
||||
like IBM mainframes which are
|
||||
\emph on
|
||||
constructed
|
||||
\emph default
|
||||
for scale-up during 24/7/365 operations.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Plain Layout
|
||||
\noindent
|
||||
\begin_inset Graphics
|
||||
filename images/MatieresCorrosives.png
|
||||
lyxscale 50
|
||||
scale 17
|
||||
|
||||
\end_inset
|
||||
|
||||
Do not mix up different hardware classes like mainframes vs contemporary
|
||||
servers.
|
||||
\end_layout
|
||||
|
||||
\begin_layout Plain Layout
|
||||
Following are more adverse effects, by incorrect usage of the term
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
:
|
||||
\end_layout
|
||||
|
||||
\end_inset
|
||||
|
||||
|
||||
\end_layout
|
||||
|
||||
\begin_layout Standard
|
||||
\noindent
|
||||
\begin_inset Graphics
|
||||
@ -6027,7 +6299,7 @@ there are no limits
|
||||
\end_inset
|
||||
|
||||
.
|
||||
Such a belief is not only wrong, it is
|
||||
Such a belief is not only fundamentally wrong, it is
|
||||
\series bold
|
||||
dangerous
|
||||
\series default
|
||||
@ -6105,7 +6377,15 @@ storage systems
|
||||
\emph on
|
||||
application classes
|
||||
\emph default
|
||||
, the term can easily
|
||||
, the term
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
scalability
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
can easily
|
||||
\series bold
|
||||
mislead
|
||||
\series default
|
||||
@ -6133,7 +6413,7 @@ evangelists
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
or advocates, this creates an
|
||||
or advocates / influencers, this creates an
|
||||
\emph on
|
||||
opportunity
|
||||
\emph default
|
||||
@ -6151,9 +6431,28 @@ noprefix "false"
|
||||
|
||||
\end_inset
|
||||
|
||||
), and for
|
||||
).
|
||||
Internal projects can be argued
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
more convincing
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
or
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
more promising
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
.
|
||||
External products or solutions can be sold more easily.
|
||||
This may
|
||||
\series bold
|
||||
tearing out money from your pocket
|
||||
tear out money from your pocket
|
||||
\series default
|
||||
.
|
||||
It may imply further bad effects, e.g.
|
||||
@ -6161,7 +6460,7 @@ tearing out money from your pocket
|
||||
\series bold
|
||||
creation of impressions
|
||||
\series default
|
||||
(or even un-proved claims) about
|
||||
(or un-proved or un-provable claims) about
|
||||
\end_layout
|
||||
|
||||
\begin_layout Itemize
|
||||
@ -6173,7 +6472,29 @@ arbitrary(!) scalability
|
||||
\end_layout
|
||||
|
||||
\begin_layout Itemize
|
||||
several further mis-guidings, some of them looking like
|
||||
|
||||
\series bold
|
||||
marketing buzzwords
|
||||
\series default
|
||||
, e.g.
|
||||
like
|
||||
\begin_inset Quotes eld
|
||||
\end_inset
|
||||
|
||||
planet scale
|
||||
\begin_inset Quotes erd
|
||||
\end_inset
|
||||
|
||||
(e.g.
|
||||
avoiding the -ing or -ability so you cannot check or disprove it), and/or
|
||||
\end_layout
|
||||
|
||||
\begin_layout Itemize
|
||||
several further
|
||||
\series bold
|
||||
mis-guidings
|
||||
\series default
|
||||
, some of them looking like
|
||||
\emph on
|
||||
deliberately not corrected
|
||||
\emph default
|
||||
@ -6432,7 +6753,17 @@ f.
|
||||
conservative communication strategy
|
||||
\emph default
|
||||
, not intended for marketing.
|
||||
Further
|
||||
Since MARS is a software component, other factors like hardware properties
|
||||
cannot be documented in
|
||||
\family typewriter
|
||||
mars-user-guide.pdf
|
||||
\family default
|
||||
, but only
|
||||
\emph on
|
||||
estimated from experiences
|
||||
\emph default
|
||||
.
|
||||
Some
|
||||
\emph on
|
||||
practical experiences
|
||||
\emph default
|
||||
@ -6559,11 +6890,11 @@ checkable
|
||||
\series bold
|
||||
certain workload
|
||||
\series default
|
||||
and/or
|
||||
and/or for a
|
||||
\series bold
|
||||
workload class
|
||||
\series default
|
||||
and/or
|
||||
and/or for an
|
||||
\series bold
|
||||
application class
|
||||
\series default
|
||||
@ -6649,7 +6980,7 @@ loss of a product line
|
||||
\series bold
|
||||
out of business
|
||||
\series default
|
||||
.
|
||||
when your competition can bypass you dramatically.
|
||||
\end_layout
|
||||
|
||||
\end_inset
|
||||
|
||||
Loading…
Reference in New Issue
Block a user