to
>>> have small number of vnodes for the versions using old allocation method
>>> because of hot-spots, so it's not an option for my particular case (v.2.1)
>>> :(
>>>
>>> [As far as I can see from the source code this new method was
2018 12:49:02 AM
To: user
Subject: Re: vnodes: high availability
I *strongly* recommend disabling dynamic snitch. I’ve seen it make latency
jump 10x.
dynamic_snitch: false is your friend.
On Jan 17, 2018, at 2:00 PM, Kyrylo Lebediev
mailto:kyrylo_lebed...@epam.com>> wrote:
Avi,
I
uary 17, 2018 2:50 PM
> To: user@cassandra.apache.org; kurt greaves
> Subject: Re: vnodes: high availability
>
> On the flip side, a large number of vnodes is also beneficial. For example,
> if you add a node to a 20-node cluster with many vnodes, each existing node
> will contribut
ks,
Kyrill
From: Avi Kivity
Sent: Wednesday, January 17, 2018 2:50 PM
To: user@cassandra.apache.org; kurt greaves
Subject: Re: vnodes: high availability
On the flip side, a large number of vnodes is also beneficial. For example, if
you add a node to a 20-node cluster with many vnodes, each exi
n.wikipedia.org
In mathematics, a combination is a selection of items from a collection, such
that (unlike permutations) the order of selection does not matter.
From: kurt greaves
Sent: Wednesday, January 17, 2018 5:43:06 AM
To: User
Subject: Re: vnodes: high avail
*From:* Jon Haddad mailto:jonathan.had...@gmail.com>> on behalf of Jon Haddad
mailto:j...@jonhaddad.com>>
*Sent:* Tuesday, January 16, 2018 8:21:33 PM
*To:* user@cassandra.apache.org <mailto:user@cassandra.apache.org>
*Subject:* Re: vnodes: high availability
pots of ownership. It should be possible to improve dramatically on
> this with deterministic ...
>
> --
> *From:* Jon Haddad on behalf of Jon Haddad <
> j...@jonhaddad.com>
> *Sent:* Tuesday, January 16, 2018 8:21:33 PM
>
> *To:* user@cass
rom: Jon Haddad on behalf of Jon Haddad
Sent: Tuesday, January 16, 2018 8:21:33 PM
To: user@cassandra.apache.org
Subject: Re: vnodes: high availability
We’ve used 32 tokens pre 3.0. It’s been a mixed result due to the randomness.
There’s going to be some imbalance, the amount of
,
> Kyrill
> From: Jon Haddad on behalf of Jon Haddad
>
> Sent: Tuesday, January 16, 2018 6:44:53 PM
> To: user
> Subject: Re: vnodes: high availability
>
> While all the token math is helpful, I have to also call out the elephant in
> the room:
>
> You have
than 32 servers
per AZ in order to to get 'reliable' cluster)
vnodes=4 seems to be better from HA + balancing trade-off
Thanks,
Kyrill
From: Jon Haddad on behalf of Jon Haddad
Sent: Tuesday, January 16, 2018 6:44:53 PM
To: user
Subject: Re: vnodes:
s to calculations of C* reliability based on which
> decisions were made.
>
> Regards,
> Kyrill
> From: kurt greaves
> Sent: Tuesday, January 16, 2018 2:16:34 AM
> To: User
> Subject: Re: vnodes: high availability
>
> Yeah it's very unlikely that you will have 2
nodes must
be seen as UP by the coordinator node as the request has specified via the...
From: Alexander Dejanovski
Sent: Tuesday, January 16, 2018 12:50:13 PM
To: user@cassandra.apache.org
Subject: Re: vnodes: high availability
Hi Kyrylo,
high availability
;d be
> grateful to get some links to calculations of C* reliability based on which
> decisions were made.
>
>
> Regards,
>
> Kyrill
> ------
> *From:* kurt greaves
> *Sent:* Tuesday, January 16, 2018 2:16:34 AM
> *To:* User
>
> *Subject:* Re: vnod
were made.
Regards,
Kyrill
From: kurt greaves
Sent: Tuesday, January 16, 2018 2:16:34 AM
To: User
Subject: Re: vnodes: high availability
Yeah it's very unlikely that you will have 2 nodes in the cluster with NO
intersecting token ranges (vnodes) for an RF of 3 (probably even 2).
if I'm wrong.
>
>
> How would the situation differ from this example by DataStax, if we had a
> real-life 6-nodes cluster with 8 vnodes on each node?
>
>
> Regards,
>
> Kyrill
>
>
> --
> *From:* Alexander Dejanovski
> *Sen
with 8 vnodes on each node?
Regards,
Kyrill
From: Alexander Dejanovski
Sent: Monday, January 15, 2018 8:14:21 PM
To: user@cassandra.apache.org
Subject: Re: vnodes: high availability
I was corrected off list that the odds of losing data when 2 nodes are
7; | uniq | grep -B2
>> -A2 '' | grep -v '' | grep -v '^--' | sort |
>> uniq | wc -l
>>
>> returned number which equals to Nnodes -1, what means that I can't switch
>> off 2 nodes at the same time w/o losing of some keyrange for CL=
--' | sort |
> uniq | wc -l
>
> returned number which equals to Nnodes -1, what means that I can't switch
> off 2 nodes at the same time w/o losing of some keyrange for CL=QUORUM.
>
>
> Thanks,
>
> Kyrill
> --
> *From:* Rahul Nee
hat means that I can't switch off 2
nodes at the same time w/o losing of some keyrange for CL=QUORUM.
Thanks,
Kyrill
From: Rahul Neelakantan
Sent: Monday, January 15, 2018 5:20:20 PM
To: user@cassandra.apache.org
Subject: Re: vnodes: high availability
N
Not necessarily. It depends on how the token ranges for the vNodes are
assigned to them. For example take a look at this diagram
http://docs.datastax.com/en/archived/cassandra/2.0/cassandra/architecture/architectureDataDistributeDistribute_c.html
In the vNode part of the diagram, you will see that
Hi,
Let's say we have a C* cluster with following parameters:
- 50 nodes in the cluster
- RF=3
- vnodes=256 per node
- CL for some queries = QUORUM
- endpoint_snitch = SimpleSnitch
Is it correct that 2 any nodes down will cause unavailability of a keyrange at
CL=QUORUM?
Regards,
K
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