[Haifux] [HAIFUX LECTURE] Replicate and Bundle (RnB) -- Shachar Raindel

Eli Billauer eli at billauer.co.il
Sat Jul 20 22:18:15 MSD 2013

On Monday, July 22nd at 18:30, Haifux will gather to hear a talk by 
Shachar Raindel:

    Replicate and Bundle (RnB) -- A Mechanism for Relieving Bottlenecks 
in Data Centers


This work addresses the scalability and efficiency of RAM-based storage 
systems wherein multiple objects must be retrieved per user request. 
Here, much of the CPU work is per server transaction, not per requested 
item. Adding servers and spreading the data across them also spreads any 
given set of requested items across more servers, thereby increasing the 
total number of server transactions per user request. The resulting poor 
scalability, dubbed the Multi-get Hole, has been reported in Web 2.0 
systems using memcached - a popular memory-based key-value storage system.

We present Replicate and Bundle (RnB), a somewhat unintuitive approach: 
rather than add CPUs, we add memory. Object replicas are mapped 
“randomly” to servers, and requested objects are bundled, selecting 
replicas so as to minimize the number of servers accessed per user 
request and thus the total CPU work per request. We studied RnB via 
simulation in the context of DRAM-based storage, utilizing micro 
benchmarks and implemented RnB modules for calibration. Our results show 
that RnB substantially reduces the number of transactions per request, 
making operation more efficient. Also, unlike most alternatives, RnB 
permits flexible growth and relatively easy deployment. Finally, in 
systems wherein data is replicated for other reasons, RnB is nearly free.


We meet in Taub building, room 6. For instructions see:

Attendance is free, and you are all invited!

Future lectures:

05/08/13 All I really need to know about bioinformatics, I learnt in
          Haifux: Boaz Goldstein


We are always interested in hearing your talks and ideas. If you wish to 
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interested in, please contact us at webmaster at haifux.org

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