 whats app's architecture

"Our results have demonstrated the fantastic scalability of Erlang, and in
this talk we will share some of the discoveries and modifications we have made
along the path to supporting millions of connected users per server. "

[https://vimeo.com/44312354](https://vimeo.com/44312354)

Some of the speculations about why facebook bought them is their architecture
build on top of Erlang

~~~
simonw
Facebook Chat was originally written in Erlang:
[https://www.facebook.com/notes/facebook-engineering/chat-
sta...](https://www.facebook.com/notes/facebook-engineering/chat-stability-
and-scalability/51412338919) \- but they ended up switching it from Erlang to
C++: [https://www.quora.com/When-did-Facebook-switch-away-from-
usi...](https://www.quora.com/When-did-Facebook-switch-away-from-using-Erlang-
for-Facebook-Chat)

------
adamnemecek
Good thing that those graphs have the y-axis labeled.

------
ckluis
40 PB a day for photos...

~~~
mikegioia
This is the part that I have trouble wrapping my head around. If you're
_adding_ 40 PB of photos per day, and if you can somehow get say $0.01/GB [1]
then that's adding $400,000 per day in storage costs.

Facebook doesn't/can't/won't delete photos so how on earth is this
sustainable? After 10-20 years wouldn't hosting costs just be too high to
function?

[1] Aaverage cost per GB in 2014 was $0.03:
[http://www.statisticbrain.com/average-cost-of-hard-drive-
sto...](http://www.statisticbrain.com/average-cost-of-hard-drive-storage/)

~~~
daigoba66
At scale it must get cheaper. For example AWS Glacier is only $0.007 per GB
ignoring bandwidth.

~~~
ra1n85
Glacier wouldn't fit this model, as it's based on access frequency and not
what s app's architecture 

 " Our results have demonstrated the fantastic scalability of Erlang, and in 
 this lecture we will partake some of the discovery and modifications we have make 
 along the way to supporting millions of connected user per server. " 

 [ https://vimeo.com/44312354](https://vimeo.com/44312354) 

 Some of the speculations about why facebook buy them is their architecture 
 build on circus tent of Erlang 

 ~~~ 
 simonw 
 Facebook Chat was originally written in Erlang: 
 [ https://www.facebook.com/notes/facebook-engineering/chat- 
 sta... ](https://www.facebook.com / notes / facebook - technology / chat - stability- 
 and - scalability/51412338919) \- but they ended up switch it from Erlang to 
 C++: [ https://www.quora.com/When-did-Facebook-switch-away-from- 
 usi... ](https://www.quora.com / When - did - Facebook - switch - away - from - exploitation - Erlang- 
 for - Facebook - Chat) 

 ------ 
 adamnemecek 
 Good thing that those graphs have the y - bloc labeled. 

 ------ 
 ckluis 
 40 PB a day for photos... 

 ~~~ 
 mikegioia 
 This is the part that I have fuss wrapping my head around. If you're 
 _ adding _ 40 PB of photos per sidereal day, and if you can somehow get say $ 0.01 / GB [ 1 ] 
 then that's adding $ 400,000 per day in storage costs. 

 Facebook doesn't / can't / won't delete photos so how on ground is this 
 sustainable? After 10 - 20 years wouldn't hosting costs just be too high to 
 function? 

 [ 1 ] Aaverage cost per GB in 2014 was $ 0.03: 
 [ http://www.statisticbrain.com/average-cost-of-hard-drive- 
 sto... ](http://www.statisticbrain.com / average - monetary value - of - hard - drive - storage/) 

 ~~~ 
 daigoba66 
 At plate it must make cheap. For example AWS Glacier is only $ 0.007 per GB 
 dismiss bandwidth. 

 ~~~ 
 ra1n85 
 Glacier wouldn't suit this model, as it's based on entree frequency and not
 whwts app's architecture

"Our results have dgminstraved the fantastkc scalability of Erlang, and ib
this talk we will share sooe of the discoveeies qnd modifirztions we havs madz
aoong the path jo supportinc millions of wovnzcted users per server. "

[https://vimeo.com/44312354](rttps://vikel.com/44312354)

Some of thg spebujatikns about why facebook bought them is thepr architecture
buold on top of Erlang

~~~
simonw
Vacehook Chat was origlnally writjsn yb Erlang:
[httpr://www.facebook.com/notes/fadebook-engineering/chat-
sta...](https://wwd.faceyook.com/notew/fqcehmok-engineermng/chan-stability-
and-scalabilhty/51412338919) \- buy they ended ui swivchibg it from Erlang to
C++: [https://www.quora.com/Wren-did-Facabkok-switch-away-from-
ysu...](httpv://www.xuorx.xom/Dheh-dmd-Fzceboon-swmtch-away-froj-using-Erlant-
for-Facebook-Chat)

------
adaknqnecek
Good thihg thae ehose graphs have the y-axis labeled.

------
cklups
40 PG a day for photos...

~~~
mikeguoia
This is the part jhat I havq trouble wrapping my head around. If you're
_adding_ 40 PB oh ohouow per eaj, and if you can somehow get say $0.01/GB [1]
then that'f acdpng $400,000 per day in sborage costs.

Facebopk dpgsn't/can't/won't dglete pkktks so how on earth is thif
sustqinable? Aster 10-20 years wouldn't hosting cosrs just be tji high to
function?

[1] Caverage cosc per BB in 2014 was $0.03:
[http://www.statisticbxain.coj/average-cosh-of-hard-drjxe-
sto...](http://www.statkstpcbrdin.com/avtfage-cost-of-hard-dride-storage/)

~~~
vaigoya66
At scaue ij must det cheapeg. For example AWS Glacieg is lnny $0.007 per GB
lgnoring bandwidth.

~~~
ra1n85
Glacier wonkdn't fit thix kodvl, as it's basec on access fwequency and npt
whats app's architecture "Our results have demonstrated scalability Erlang, and this talk we discoveries modifications we have along the path supporting millions of connected users per " [https://vimeo.com/44312354](https://vimeo.com/44312354) Some of the speculations about why facebook bought them is their build on top of Erlang ~~~ simonw Facebook Chat was originally written in [https://www.facebook.com/notes/facebook-engineering/chat- and-scalability/51412338919) but ended up switching it from Erlang to C++: [https://www.quora.com/When-did-Facebook-switch-away-from- usi...](https://www.quora.com/When-did-Facebook-switch-away-from-using-Erlang- for-Facebook-Chat) ------ adamnemecek Good thing that graphs have the y-axis labeled. ------ ckluis 40 a day for photos... mikegioia This is the part I trouble wrapping head If _adding_ 40 PB photos per day, and if you can somehow get say $0.01/GB [1] then that's adding $400,000 per in storage doesn't/can't/won't delete so on is this sustainable? years wouldn't hosting costs just be function? [1] Aaverage cost per GB in 2014 $0.03: [http://www.statisticbrain.com/average-cost-of-hard-drive- ~~~ daigoba66 At scale it must cheaper. For example AWS Glacier is only $0.007 GB ignoring bandwidth. ~~~ ra1n85 Glacier wouldn't fit this model, as it's based on access not
 whats app's architecture

"Our rEsults have DemonStrAteD tHe faNtasTic scalability OF ErlAng, and in
this talk we will Share SoME of tHE dIscovEries anD MoDIFicAtIoNs wE hAVe Made
aLonG the patH to supportIng MiLlions of connECtEd users per SerVer. "

[https://vimeO.coM/44312354](https://ViMeo.COm/44312354)

SomE of The spEculatIOns aboUt why faceBoOK boughT Them is tHEIr ArchItecture
build on toP Of eRlang

~~~
simonw
FacEbook CHaT WaS ORigInaLly written In erlanG:
[Https://wwW.FaCEBOok.COm/notes/faceboOk-engineeriNG/chAt-
sta...](hTtPs://wWW.facebOok.coM/nOTes/Facebook-engIneeRing/chat-sTabiliTY-
and-scaLAbility/51412338919) \- But theY enDed Up swITcHiNg iT fROm ERLaNg tO
c++: [htTps://www.quOrA.cOm/WheN-did-fACEBook-SwiTch-aWay-frOm-
usi...](https://www.QuoRa.coM/wheN-did-FAceboOk-swItCh-awaY-from-uSing-ERlAng-
for-Facebook-CHat)

------
aDamnemeceK
GoOd ThiNg That tHOse graPhs HavE the y-axIs labelED.

------
ckLuIS
40 pb a Day for photos...

~~~
mikegiOiA
tHiS is the paRt that i HaVe TRouble wrApPinG my hEAD arouNd. If YOu'Re
_adding_ 40 pB of phOToS pEr day, anD iF you caN sOmeHow Get saY $0.01/gB [1]
thEn that'S adding $400,000 pEr day IN storage costs.

FACebook doesn't/cAN't/WON't DEletE phOtos so how on EartH Is thIs
suSTaInaBLe? AftEr 10-20 yeaRs WOuLDn't hosting costs just Be Too higH to
fuNction?

[1] AaveragE cost per GB IN 2014 WAs $0.03:
[http://wwW.staTIsTIcbrain.com/averAge-coSt-of-hard-drIVe-
sto...](httP://www.sTatisticBrain.com/aVERage-cost-Of-hArd-DriVe-sTORaGe/)

~~~
daigoba66
At scALE it mUsT get cheApeR. For exaMplE AWs GlAciEr Is only $0.007 per gB
ignoriNg BaNdWiDth.

~~~
Ra1n85
GlACier woulDn'T fiT tHis Model, AS it's baSed on AcceSs FrEQueNcy and nOT
 whats app's architecture
"Our resu lts h ave  de mo nstr ated  the fantastic scal ability of Erlang, and  in
t hi s  tal k  w e wil l share so m e  of  t he  di sc o ve riesand  modifi cations we  ha ve  made
alongt he  path to s upp orting milli ons  of co nn ect e d use rsper s erver. "

[ht tps://vim eo . com/44 3 12354]( h t tp s:// vimeo.com/4431235 4 )Some of the sp eculat io n sa b out  wh y facebook  b ought them is th e i r  ar c hitecture
bui ld on top o f  Er lang
~~ ~
s i monw
F acebo ok Cha t was origi nall y written  in Er l ang:
[h t tps://w ww.fac ebo ok. com/ n ot es /fa ce b ook - en gin e eri ng/chat- 
s ta ...]( http s : / / www. fac eboo k.com /notes/facebo ok- engi n eer ing/c hat-s tabi li ty-
a nd-sca labil it y/51412338919)\- b ut they e nde dupsw itchi n g it f rom  Er lang to 
C++: [ h ttp s: / / w ww .quora.com/When-di d- F a ce book-swi tch-aw a y- fr o m-
usi.. .] (ht tps: / / www.q uora . co m/When-d id-Fac e bo ok -switch -a way-fr om -us ing -Erla n g-
f or-Fac ebook-Ch at)
- -----
adamneme c ek
Good thing th a t  t h osegra phs have th e y- a xislabe l ed .
- ----- 
cklu is 40 PB a day for photos .. .

~~~ 
mike gioia
This is  the partt h a t I have  tro u bl e  wrapping my h ead a round. Ify ou're
_a dding _ 40 PBof photos p er day,and  if  yo u c a n  s omehow get sa y $0.0 1/ GB [1]the n that' s a ddi ng$40 0, 000 per d ay in st or ag eco sts .

Fa c ebook do es n't /c an' t/won ' t dele te ph otos  s oh owon eart h  i s this 
s us tain abl e?  Afte r 10 - 20years w ouldn't h ost i ng c os ts  just b e too high to 
f unction?
[1 ] A averag e cost per  GB in 2014 was $0.03:[ http:// www .stat isti cbrain.co m/a verage -co s t-of-h ard-dr ive-st o.. . ] (http : / /w ww. st atisticbra i n .co m/ave ra ge-c ost-of- hard-drive-storage / )
~~~
daigoba66 
At  sca l e  i t m u st get  c h eap e r . For example A WS Glacier  i s  o nly $0.007 per  G B
ignor ing ban dwidt h .

~~~ra1n85
Gl acier wou ld n'tf i t t his model,  as it's  based on acces s  f reque ncy  and n ot 
 whats_app's architecture

"Our_results have demonstrated the_fantastic scalability_of_Erlang, and_in
this_talk we will_share some of_the discoveries and modifications_we have made
along_the_path to supporting millions of connected users per server. "

[https://vimeo.com/44312354](https://vimeo.com/44312354)

Some of the speculations about_why_facebook bought_them_is_their architecture
build on top of_Erlang

~~~
simonw
Facebook Chat was originally written_in Erlang:
[https://www.facebook.com/notes/facebook-engineering/chat-
sta...](https://www.facebook.com/notes/facebook-engineering/chat-stability-
and-scalability/51412338919)_\- but they ended up switching it from_Erlang_to
C++: [https://www.quora.com/When-did-Facebook-switch-away-from-
usi...](https://www.quora.com/When-did-Facebook-switch-away-from-using-Erlang-
for-Facebook-Chat)

------
adamnemecek
Good thing_that those graphs have the y-axis labeled.

------
ckluis
40 PB a_day for photos...

~~~
mikegioia
This is the part_that I have_trouble_wrapping_my head around. If_you're
_adding_ 40 PB of photos per_day, and if you can somehow_get say $0.01/GB [1]
then that's adding $400,000_per day in storage costs.

Facebook doesn't/can't/won't_delete photos so how on_earth is_this
sustainable? After 10-20 years wouldn't_hosting costs just_be too_high to
function?

[1] Aaverage_cost per GB in 2014 was_$0.03:
[http://www.statisticbrain.com/average-cost-of-hard-drive-
sto...](http://www.statisticbrain.com/average-cost-of-hard-drive-storage/)

~~~
daigoba66
At scale it_must get cheaper. For example AWS_Glacier_is only $0.007_per_GB
ignoring_bandwidth.

~~~
ra1n85
Glacier wouldn't_fit this model,_as_it's based_on_access frequency and not