EACH_QUORUM for one DC
Hi, If there is only one DC, can we still use EACH_QUORUM for write? We only have one DC now, but will build another one in future and like to use EACH_QUORUM when there are two. But like to know if it's good to use EACH_QUORUM with the current 1 DC. And if there are two DCs but in some cases one whole DC cluster is down, does that mean all the writes are going to fail? Thanks, Chong
Re: tokens and RF for multiple phases of deployment
I followed the doc to add the new node. After the nodetool repair, the
'Load' on the new node in DC2 increased to 250M. But the 'Owns' col are
still 50%, 50%, 0%, and I guess it's OK because the new token value is 1?
Thanks,
Chong
On Thu, May 31, 2012 at 9:52 PM, aaron morton aa...@thelastpickle.comwrote:
The ring (2 in DC1, 1 in DC2) looks OK, but the load on the new node in
DC2 is almost 0%.
yeah, thats the way it will look.
But all the other rows are not in the new node. Do I need to copy the data
files from a node in DC1 to the new node?
How did you add the node ? (see
http://www.datastax.com/docs/1.0/operations/cluster_management#adding-nodes-to-a-cluster
)
if in doubt run nodetool repair on the new node.
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 1/06/2012, at 3:46 AM, Chong Zhang wrote:
Thanks Aaron.
I might use LOCAL_QUORUM to avoid the waiting on the ack from DC2.
Another question, after I setup a new node with token +1 in a new DC, and
updated a CF with RF {DC1:2, DC2:1}. When i update a column on one node in
DC1, it's also updated in the new node in DC2. But all the other rows are
not in the new node. Do I need to copy the data files from a node in DC1 to
the new node?
The ring (2 in DC1, 1 in DC2) looks OK, but the load on the new node in
DC2 is almost 0%.
Address DC RackStatus State Load
OwnsToken
85070591730234615865843651857942052864
10.10.10.1DC1 RAC1Up Normal 313.99 MB
50.00% 0
10.10.10.3DC2 RAC1Up Normal 7.07 MB
0.00% 1
10.10.10.2DC1 RAC1Up Normal 288.91 MB
50.00% 85070591730234615865843651857942052864
Thanks,
Chong
On Thu, May 31, 2012 at 5:48 AM, aaron morton aa...@thelastpickle.comwrote:
Could you provide some guide on how to assign the tokens in this growing
deployment phases?
background
http://www.datastax.com/docs/1.0/install/cluster_init#calculating-tokens-for-a-multi-data-center-cluster
Start with tokens for a 4 node cluster. Add the next 4 between between
each of the ranges. Add 8 in the new DC to have the same tokens as the
first DC +1
Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
No. It will fail if there are not enough nodes available in the first DC.
We'd like to keep both write and read on the same cluster.
Writes go to all replicas. Using EACH_QUORUM means the client in the
first DC will be waiting for the quorum from the second DC to ack the
write.
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 31/05/2012, at 3:20 AM, Chong Zhang wrote:
Hi all,
We are planning to deploy a small cluster with 4 nodes in one DC first,
and will expend that to 8 nodes, then add another DC with 8 nodes for fail
over (not active-active), so all the traffic will go to the 1st cluster,
and switch to 2nd cluster if the whole 1st cluster is down or
on maintenance.
Could you provide some guide on how to assign the tokens in this growing
deployment phases? I looked at some docs but not very clear on how to
assign tokens on the fail-over case.
Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
We'd like to keep both write and read on the same cluster.
Thanks in advance,
Chong
Re: tokens and RF for multiple phases of deployment
Thanks Aaron.
I might use LOCAL_QUORUM to avoid the waiting on the ack from DC2.
Another question, after I setup a new node with token +1 in a new DC, and
updated a CF with RF {DC1:2, DC2:1}. When i update a column on one node in
DC1, it's also updated in the new node in DC2. But all the other rows are
not in the new node. Do I need to copy the data files from a node in DC1 to
the new node?
The ring (2 in DC1, 1 in DC2) looks OK, but the load on the new node in DC2
is almost 0%.
Address DC RackStatus State LoadOwns
Token
85070591730234615865843651857942052864
10.10.10.1DC1 RAC1Up Normal 313.99 MB 50.00%
0
10.10.10.3DC2 RAC1Up Normal 7.07 MB
0.00% 1
10.10.10.2DC1 RAC1Up Normal 288.91 MB 50.00%
85070591730234615865843651857942052864
Thanks,
Chong
On Thu, May 31, 2012 at 5:48 AM, aaron morton aa...@thelastpickle.comwrote:
Could you provide some guide on how to assign the tokens in this growing
deployment phases?
background
http://www.datastax.com/docs/1.0/install/cluster_init#calculating-tokens-for-a-multi-data-center-cluster
Start with tokens for a 4 node cluster. Add the next 4 between between
each of the ranges. Add 8 in the new DC to have the same tokens as the
first DC +1
Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
No. It will fail if there are not enough nodes available in the first DC.
We'd like to keep both write and read on the same cluster.
Writes go to all replicas. Using EACH_QUORUM means the client in the first
DC will be waiting for the quorum from the second DC to ack the write.
Cheers
-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com
On 31/05/2012, at 3:20 AM, Chong Zhang wrote:
Hi all,
We are planning to deploy a small cluster with 4 nodes in one DC first,
and will expend that to 8 nodes, then add another DC with 8 nodes for fail
over (not active-active), so all the traffic will go to the 1st cluster,
and switch to 2nd cluster if the whole 1st cluster is down or
on maintenance.
Could you provide some guide on how to assign the tokens in this growing
deployment phases? I looked at some docs but not very clear on how to
assign tokens on the fail-over case.
Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write
and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster?
We'd like to keep both write and read on the same cluster.
Thanks in advance,
Chong
tokens and RF for multiple phases of deployment
Hi all, We are planning to deploy a small cluster with 4 nodes in one DC first, and will expend that to 8 nodes, then add another DC with 8 nodes for fail over (not active-active), so all the traffic will go to the 1st cluster, and switch to 2nd cluster if the whole 1st cluster is down or on maintenance. Could you provide some guide on how to assign the tokens in this growing deployment phases? I looked at some docs but not very clear on how to assign tokens on the fail-over case. Also if we use the same RF (3) in both DC, and use EACH_QUORUM for write and LOCAL_QUORUM for read, can the read also reach to the 2nd cluster? We'd like to keep both write and read on the same cluster. Thanks in advance, Chong
