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Posted to user@cassandra.apache.org by zhangyf2007 <zh...@gmail.com> on 2009/12/23 04:07:40 UTC
Why seed can't startup in Bootstrap mode ?
I found that if one node has been set as seed it can't startup in
Bootstarp mode even though AutoBootstrap is "true". Why the seed node
can't startup in Bootstrap mode ?
Thanks!
Re: Why seed can't startup in Bootstrap mode ?
Posted by Jonathan Ellis <jb...@gmail.com>.
On Wed, Dec 23, 2009 at 3:43 AM, <ma...@gmail.com> wrote:
> So, once a seed crash and damage it's data, we cannot wipe the node and
> re-bootstrap, because node cannot bootstrap if configured as seed.
> Also we can not re-configure node to a non-seed, because that will reduce
> total number of seeds,
> so eventually all old data will lost(one by one), or there is no seed(all
> seed was re-configure to non-seed).
>
> Am I right??
No. :)
You can re-designate nodes as seeds after bootstrapping, as I
mentioned in my first reply.
-Jonathan
RE: Why seed can't startup in Bootstrap mode ?
Posted by ma...@gmail.com.
So, once a seed crash and damage it's data, we cannot wipe the node and
re-bootstrap, because node cannot bootstrap if configured as seed.
Also we can not re-configure node to a non-seed, because that will reduce
total number of seeds,
so eventually all old data will lost(one by one), or there is no seed(all
seed was re-configure to non-seed).
Am I right??
---------END----------
-----Original Message-----
From: Jonathan Ellis [mailto:jbellis@gmail.com]
Sent: Wednesday, December 23, 2009 11:46 AM
To: cassandra-user@incubator.apache.org
Subject: Re: Why seed can't startup in Bootstrap mode ?
On Tue, Dec 22, 2009 at 9:39 PM, zhangyf2007 <zh...@gmail.com> wrote:
> Consider the following scene:
> 1) the ReplicationFactor is 3
> 2) the cluster has 3 nodes and all the nodes are seed nodes
> 3) one node is dead while the data it managed is also damaged
unfortunately
> 4) it starts up but it can't request any data from other node
you can either repair the existing data or wipe the node, remove it
from the cluster, and rebootstrap.
this has nothing to do with being seeds; bootstrapping is for adding
new nodes to the cluster, doing it to a node that already has data on
it is wrong.
see http://wiki.apache.org/cassandra/Operations
-Jonathan
Re: RE: Why seed can't startup in Bootstrap mode ?
Posted by Jonathan Ellis <jb...@gmail.com>.
On Wed, Dec 23, 2009 at 10:26 AM, Brian Burruss <bb...@real.com> wrote:
> my understanding ... if a node crashes and loses data, simply restarting it and doing a node repair might work.
>
> bootstrapping is for adding new nodes, correct?
yes and yes, although if you lose enough data it may be faster to just
wipe it and start over w/ bootstrap.
RE: RE: Why seed can't startup in Bootstrap mode ?
Posted by Brian Burruss <bb...@real.com>.
my understanding ... if a node crashes and loses data, simply restarting it and doing a node repair might work.
bootstrapping is for adding new nodes, correct?
________________________________________
From: Coe, Robin [robin.coe@bluecoat.com]
Sent: Wednesday, December 23, 2009 7:20 AM
To: cassandra-user@incubator.apache.org
Subject: RE: RE: Why seed can't startup in Bootstrap mode ?
> Yes, although IMO to avoid confusion you will want to re-standardize on a single set of seeds as soon as possible.
Sounds like the behaviour of seeds needs to be explained in the Operations guide. E.g., under what conditions would it be necessary to do anything with A other than restart it? Are there use cases that govern changing the seeds:
1. why you would need to change the seeds
2. what operations would be involved to reconfigure the cluster?
In a fully operational cluster, is there any special logic attached to a seed that can't be accommodated by a node that gets bootstrapped?
-Robin.
-----Original Message-----
From: Jonathan Ellis [mailto:jbellis@gmail.com]
Sent: December 23, 2009 9:47 AM
To: cassandra-user@incubator.apache.org
Subject: Re: RE: Why seed can't startup in Bootstrap mode ?
2009/12/23 XL.Pan <pa...@sina.com>:
> I think you can avoid this , eg :
> A, B, C is seed node and D, E is non-seed. A crash and damage.
>
> 1) re-configure the node A to a non-seed;
> 2) starting the non-seed nood A will re-bootstrap;
> 3) Though the original seed nodes will decrease 1, any other node, eg D, can re-configure other nodes, eg B, C, E, as seed nodes.
> 4) Then the seed nodes in the ring will be :
> Node->Seeds List
> A --> B, C, D;
> B --> A, B, C;
> C --> A, B, C;
> D --> B, C, E;
> E --> A, B, C;
>
> Am I right?? ;-)
Yes, although IMO to avoid confusion you will want to re-standardize
on a single set of seeds as soon as possible.
-Jonathan
RE: RE: Why seed can't startup in Bootstrap mode ?
Posted by "Coe, Robin" <ro...@bluecoat.com>.
> Yes, although IMO to avoid confusion you will want to re-standardize on a single set of seeds as soon as possible.
Sounds like the behaviour of seeds needs to be explained in the Operations guide. E.g., under what conditions would it be necessary to do anything with A other than restart it? Are there use cases that govern changing the seeds:
1. why you would need to change the seeds
2. what operations would be involved to reconfigure the cluster?
In a fully operational cluster, is there any special logic attached to a seed that can't be accommodated by a node that gets bootstrapped?
-Robin.
-----Original Message-----
From: Jonathan Ellis [mailto:jbellis@gmail.com]
Sent: December 23, 2009 9:47 AM
To: cassandra-user@incubator.apache.org
Subject: Re: RE: Why seed can't startup in Bootstrap mode ?
2009/12/23 XL.Pan <pa...@sina.com>:
> I think you can avoid this , eg :
> A, B, C is seed node and D, E is non-seed. A crash and damage.
>
> 1) re-configure the node A to a non-seed;
> 2) starting the non-seed nood A will re-bootstrap;
> 3) Though the original seed nodes will decrease 1, any other node, eg D, can re-configure other nodes, eg B, C, E, as seed nodes.
> 4) Then the seed nodes in the ring will be :
> Node->Seeds List
> A --> B, C, D;
> B --> A, B, C;
> C --> A, B, C;
> D --> B, C, E;
> E --> A, B, C;
>
> Am I right?? ;-)
Yes, although IMO to avoid confusion you will want to re-standardize
on a single set of seeds as soon as possible.
-Jonathan
Re: RE: Why seed can't startup in Bootstrap mode ?
Posted by Jonathan Ellis <jb...@gmail.com>.
2009/12/23 XL.Pan <pa...@sina.com>:
> I think you can avoid this , eg :
> A, B, C is seed node and D, E is non-seed. A crash and damage.
>
> 1) re-configure the node A to a non-seed;
> 2) starting the non-seed nood A will re-bootstrap;
> 3) Though the original seed nodes will decrease 1, any other node, eg D, can re-configure other nodes, eg B, C, E, as seed nodes.
> 4) Then the seed nodes in the ring will be :
> Node->Seeds List
> A --> B, C, D;
> B --> A, B, C;
> C --> A, B, C;
> D --> B, C, E;
> E --> A, B, C;
>
> Am I right?? ;-)
Yes, although IMO to avoid confusion you will want to re-standardize
on a single set of seeds as soon as possible.
-Jonathan
Re: RE: Why seed can't startup in Bootstrap mode ?
Posted by "XL.Pan" <pa...@sina.com>.
I think you can avoid this , eg :
A, B, C is seed node and D, E is non-seed. A crash and damage.
1) re-configure the node A to a non-seed;
2) starting the non-seed nood A will re-bootstrap;
3) Though the original seed nodes will decrease 1, any other node, eg D, can re-configure other nodes, eg B, C, E, as seed nodes.
4) Then the seed nodes in the ring will be :
Node->Seeds List
A --> B, C, D;
B --> A, B, C;
C --> A, B, C;
D --> B, C, E;
E --> A, B, C;
Am I right?? ;-)
------------------
XL.Pan
2009-12-23
-------------------------------------------------------------
发件人：mail.list.steel.mental
发送日期：2009-12-23 17:43:29
收件人：cassandra-user@incubator.apache.org
抄送：
主题：RE: Why seed can't startup in Bootstrap mode ?
So, once a seed crash and damage it's data, we cannot wipe the node and
re-bootstrap, because node cannot bootstrap if configured as seed.
Also we can not re-configure node to a non-seed, because that will reduce
total number of seeds,
so eventually all old data will lost(one by one), or there is no seed(all
seed was re-configure to non-seed).
Am I right??
---------END----------
-----Original Message-----
From: Jonathan Ellis [mailto:jbellis@gmail.com]
Sent: Wednesday, December 23, 2009 11:46 AM
To: cassandra-user@incubator.apache.org
Subject: Re: Why seed can't startup in Bootstrap mode ?
On Tue, Dec 22, 2009 at 9:39 PM, zhangyf2007 <zh...@gmail.com> wrote:
> Consider the following scene:
> 1) the ReplicationFactor is 3
> 2) the cluster has 3 nodes and all the nodes are seed nodes
> 3) one node is dead while the data it managed is also damaged
unfortunately
> 4) it starts up but it can't request any data from other node
you can either repair the existing data or wipe the node, remove it
from the cluster, and rebootstrap.
this has nothing to do with being seeds; bootstrapping is for adding
new nodes to the cluster, doing it to a node that already has data on
it is wrong.
see http://wiki.apache.org/cassandra/Operations
-Jonathan
Re: Why seed can't startup in Bootstrap mode ?
Posted by Jonathan Ellis <jb...@gmail.com>.
On Tue, Dec 22, 2009 at 9:39 PM, zhangyf2007 <zh...@gmail.com> wrote:
> Consider the following scene:
> 1) the ReplicationFactor is 3
> 2) the cluster has 3 nodes and all the nodes are seed nodes
> 3) one node is dead while the data it managed is also damaged unfortunately
> 4) it starts up but it can't request any data from other node
you can either repair the existing data or wipe the node, remove it
from the cluster, and rebootstrap.
this has nothing to do with being seeds; bootstrapping is for adding
new nodes to the cluster, doing it to a node that already has data on
it is wrong.
see http://wiki.apache.org/cassandra/Operations
-Jonathan
Re: Why seed can't startup in Bootstrap mode ?
Posted by zhangyf2007 <zh...@gmail.com>.
Consider the following scene:
1) the ReplicationFactor is 3
2) the cluster has 3 nodes and all the nodes are seed nodes
3) one node is dead while the data it managed is also damaged unfortunately
4) it starts up but it can't request any data from other node
Can cassandra replicate automatically the data whose number of duplicate
is less than ReplicationFactor?
thanks!
Jonathan Ellis 写道:
> Seeds are supposed to be always part of the cluster by design, so
> adding one in bootstrap mode makes no sense.
>
> If you need to add seeds to your cluster, designate existing nodes as such.
>
> 2009/12/22 zhangyf2007 <zh...@gmail.com>:
>
>> I found that if one node has been set as seed it can't startup in
>> Bootstarp mode even though AutoBootstrap is "true". Why the seed node
>> can't startup in Bootstrap mode ?
>>
>> Thanks!
>>
>>
>
>
--
*Name:* Jeff Chang
*| MSN:* zhangyf2007@gmail.cn
| *Mail:* zhangyf2007@gmail.com
Re: Why seed can't startup in Bootstrap mode ?
Posted by Jonathan Ellis <jb...@gmail.com>.
Seeds are supposed to be always part of the cluster by design, so
adding one in bootstrap mode makes no sense.
If you need to add seeds to your cluster, designate existing nodes as such.
2009/12/22 zhangyf2007 <zh...@gmail.com>:
> I found that if one node has been set as seed it can't startup in
> Bootstarp mode even though AutoBootstrap is "true". Why the seed node
> can't startup in Bootstrap mode ?
>
> Thanks!
>