Errata

Hadoop Operations

Errata for Hadoop Operations

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The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted By Date submitted Date corrected
Printed
Page 63
3rd paragraph / listing of vm.overcommit_memory settings

In the description of the three vm.overcommit_memory settings (0, 1, and 2), the description of options 1 and 2 are reversed. The text with value 1 actually describes 2 and vice versa.

Additionally, the formula used in the explanation of option 1, as written, is not correct. The formula used when calculating the amount of allocation to permit is actually the total amount of swap space plus R% of the system memory, where R is the value of vm.overcommit_ratio kernel parameter. For example, a system with 1 GB of swap space, 1 GB of physical RAM, and a vm.overcommit_ratio setting of 50 would permit up to 1.5 GB of memory to be allocated.

The definition of value 0 (zero) is not as precise as it should be. It implies no over commit is permitted which isn't true. In fact, the kernel permits a "reasonable, minimal amount of overcommit, based on internal (undocumented) heuristics."

 Eric Sammer
 		 Oct 29, 2012 
Printed
Page 73
Figure 4-6

In figure 4-6, the top row of switches are labeled as having 48 x 1GbE ports. This is a typo. This tier of four switches should have 48 x 10GbE ports. The text that describes the figure states the correct port rate of 10GbE.

Thanks to Andy Isaacson for finding this.

 Eric Sammer
 		 Nov 15, 2012 
ePub
Page 1305
e-book location 1305, second paragraph in the section on YARN in chapter 3

The second sentence of the second paragraph of the section on YARN in Chapter 3 contains a double semicolon, as reproduced below. Additionally, I think that this should probably be a comma instead of a (single) semicolon.

The resource management aspect of the jobtracker is run as a new daemon called the resource manager;; a separate daemon responsible for creating and allocating resources to multiple applications.

Note from the Author or Editor:
This error also occurs on page 38 (2nd paragraph, 2nd sentence) of the print edition, but rather than two semicolons, it is a comma followed by a semicolon. It should be a single semicolon.

 Gabriel Reid  Oct 28, 2012