Engineering @ Facebook's Notes | Facebook
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Saved by 9 people (0 private), first by anonymouse user on 2009-05-01
- Navneetk on 2009-09-29 - Tags FaceBook , Infrastructure , Architecture , Hardware , Performance , Read-Write
- Alexpopescu on 2009-05-26 - Tags architecture , highscalability , Facebook
- Svenouille on 2009-05-04 - Tags facebook , storage
- Geheimdienst on 2009-05-02 - Tags dev , scale
- Joel on 2009-05-02 - Tags facebook , Architecture , photo , storage
Public Sticky notes
Facebook generates and stores four images of different sizes, which translates to a total of 60 billion images and 1.5PB of storage. The current growth rate is 220 million new photos per week, which translates to 25TB of additional storage consumed weekly. At the peak there are 550,000 images served per second.
Highlighted by mattcoxonline
on 2009-05-01 by mattcoxonline
Woah! That's some serious bandwidth.
Since each image is stored in its own file, there is an enormous amount of
metadata generated on the storage tier due to the namespace directories and file
inodes. The amount of metadata far exceeds the caching abilities of the NFS
storage tier, resulting in multiple I/O operations per photo upload or read
request. The whole photo serving infrastructure is bottlenecked on the high
metadata overhead of the NFS storage tier, which is one of the reasons why
Facebook relies heavily on CDNs to serve photos
Highlighted by navneetk
RAID-6 partition managed by the hardware RAID controller. RAID-6 provides
adequate redundancy and excellent read performance while keeping the storage
cost down
Highlighted by navneetk
The poor write performance is partially mitigated by the RAID controller NVRAM
write-back cache. Since the reads are mostly random, the NVRAM cache is fully
reserved for writes. The disk caches are disabled in order to guarantee data
consistency in the event of a crash or a power loss
Highlighted by navneetk
Public Comment