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Date: Sun, 31 Mar 2013 18:30:48 +0200
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 <CADfVb55PQ+2RjDK6=JRP=uTMcBi80h_x-w2CQELeAr1udnPBOw@mail.gmail.com>
Subject: Re: Who splits the file into blocks
From: Jens Scheidtmann <jens.scheidtmann@gmail.com>
To: user@hadoop.apache.org, Sai Sai <saigraph@yahoo.in>
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Dear Sai Sai,

"Hadoop, the definitive guide" says regarding default replica placement:

- first replica is placed on the same node as the client (lowest bandwidth
penalty).
- second replica is placed off-rack, at a random node of the other rack
(avoiding busy racks).
- third replicate is placed on random node on rack where second replica is
stored.
- other replicas are placed on random nodes of the cluster (avoiding busy
racks).

If client is not on the cluster, first replica is placed on a random node
(avoiding busy racks).

Best regards,


Jens

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<div dir=3D"ltr"><div><div><div><div><div><div>Dear Sai Sai,<br><br></div>&=
quot;Hadoop, the definitive guide&quot; says regarding default replica plac=
ement:<br><br></div>- first replica is placed on the same node as the clien=
t (lowest bandwidth penalty).<br>
</div>- second replica is placed off-rack, at a random node of the other ra=
ck (avoiding busy racks). <br></div>- third replicate is placed on random n=
ode on rack where second replica is stored.<br>- other replicas are placed =
on random nodes of the cluster (avoiding busy racks).<br>
<br></div><div>If client is not on the cluster, first replica is placed on =
a random node (avoiding busy racks).<br></div><div><br></div>Best regards,<=
br><br><br></div>Jens<br></div>

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