incubator-cassandra-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Anthony Molinaro <antho...@alumni.caltech.edu>
Subject [anthonym@alumni.caltech.edu: Clarification on Ring operations in Cassandra 0.5.1]
Date Sat, 17 Apr 2010 22:56:34 GMT
Hi, sorry for the forward to dev, but haven't heard anything on users
yet.

-Anthony

----- Forwarded message from Anthony Molinaro <anthonym@alumni.caltech.edu> -----

From: Anthony Molinaro <anthonym@alumni.caltech.edu>
Subject: Clarification on Ring operations in Cassandra 0.5.1
To: user@cassandra.apache.org
Date: Thu, 15 Apr 2010 16:10:44 -0700
User-Agent: Mutt/1.4.2.3i

Hi,

  I have a cluster running on ec2, and would like to do some ring
management.  Specifically, I'd like to replace an existing node
without another node (I want to change the instance type).

  I was looking over http://wiki.apache.org/cassandra/Operations
and it seems like I could do something like.

1) shutdown cassandra on instance I want to replace
2) create a new instance, start cassandra with AutoBootstrap = true
3) run nodeprobe removetoken against the token of the instance I am
   replacing

Then according to the 'Handling failure' the new instance will "find the
appropriate position automatically".  However, it's not clear to me
if this means it will take the same range as the shutdown node or not,
because normally AutoBootstrap == true means it will take "half the keys
from the node with the most disk space used." (from the 'Bootstrap' section).

So will the process I describe above result in what I want, a new node
replacing an old one?

Also, if the new instance takes over the range of the old instance how
does removetoken know which instance to remove, does it remove the Down
instance?

Another hopefully minor question, if I bring up a new node with
AutoBootstrap = false, what happens?
Does it join the ring but without data and without token range?
Can I then 'nodeprobe move <token for range I want to take over>', and
achieve the same as step 2 above?

Thanks,

-Anthony

-- 
------------------------------------------------------------------------
Anthony Molinaro                           <anthonym@alumni.caltech.edu>

----- End forwarded message -----

-- 
------------------------------------------------------------------------
Anthony Molinaro                           <anthonym@alumni.caltech.edu>

Mime
View raw message