대용량 cassandra를 운영한다는 것은 좀 공부가 필요한 것 같다. redis 이상의 운영 노하우가 필요한 것 같다. 

특히 compaction이나 node repair를 하다가 cassandra를 읽는 부분에서 timeout나고 에러 뜨고 장난아니다.

dry-run 이런 옵션이 nodetool에 없기에 공부를 반드시 많이하고 다른 곳에서는 compaction을 어떻게 하는지 살펴볼 필요가 있다. 

http://www.datastax.com/dev/blog/repair-in-cassandra

Cassandra 1.2 introduced a new option to repair to help manage the problems caused by the nodes all repairing with each other at the same time, it is call a snapshot repair, or sequential repair. As of Cassandra 2.1, sequential repair is the default, and the old parallel repair an option

http://docs.datastax.com/en/archived/cassandra_win/3.x/cassandra/tools/toolsRepair.html

Incremental repair is the default for Cassandra 2.2 and later, and full repair is the default in Cassandra 2.1 and earlier. In Cassandra 2.2 and later, when a full repair is run, SSTables are marked as repaired and anti-compacted. Parallel repair is the default for Cassandra 2.2 and later, and sequential repair is the default in Cassandra 2.1 and earlier.

$ nodetool repair --google_plus  recent_relation

 이건 에러가 발생한다.

$ nodetool repair -- google_plus  recent_relation

성공 

$ export –p

export LOGNAME=samuel.kim

export PATH=/bin:/usr/bin:.

export TIMEOUT=600

export TZ=EST5EDT

$ export xxx=1

$ export –p

export LOGNAME=samuel.kim

export PATH=/bin:/usr/bin:.

export TIMEOUT=600

export TZ=EST5EDT

[~] echo :$PS1:

:[\w]\[\033[00m\] :

$ PS1=" \"$PWD\" "

 "/Users/samuel.kim"

"/Users/samuel.kim" PS1="$ "

$

$ PS1="명령 내려주세요 $ "

명령 내려주세요 $

명령 내려주세요 $

$ PS1="\H $ "

google-MacBook-Air-100.local $

google-MacBook-Air-100.local $

$ echo :$PS2:

:> :

$  for x in 10 20 30

> do

> echo $x

> done

10

20

30

$ for x in 10 20 30

 do

 echo $x

 done

10

20

30

$ man bash

PROMPTING

       When executing interactively, bash displays the primary prompt  PS1

       when  it  is  ready to read a command, and the secondary prompt PS2

       when it needs more input to complete a command.  Bash allows  these

       prompt strings to be customized by inserting a number of backslash-

       escaped special characters that are decoded as follows:

              \a     an ASCII bell character (07)

              \d     the date in "Weekday Month Date" format  (e.g.,  "Tue

                     May 26")

              \D{format}

                     the format is passed to strftime(3) and the result is

                     inserted into the  prompt  string;  an  empty  format

                     results  in  a  locale-specific  time representation.

                     The braces are required

              \e     an ASCII escape character (033)

              \h     the hostname up to the first `.'

              \H     the hostname

              \j     the number of jobs currently managed by the shell

              \l     the basename of the shell's terminal device name

              \n     newline

              \r     carriage return

              \s     the name of the shell, the basename of $0  (the  por-

                     tion following the final slash)

              \t     the current time in 24-hour HH:MM:SS format

              \T     the current time in 12-hour HH:MM:SS format

              \@     the current time in 12-hour am/pm format

              \A     the current time in 24-hour HH:MM format

              \u     the username of the current user

              \v     the version of bash (e.g., 2.00)