y is over 100 ms which is really
> really slow. I am seeing less than 3ms reads for my cluster which is on
> SSD.
> Can you also check the nodetool cfhistorgram, it tells you more about the
> number of SSTable involved and read/write latency. Somtimes average doesn't
> tell you t
D.
>>>> Can you also check the nodetool cfhistorgram, it tells you more about the
>>>> number of SSTable involved and read/write latency. Somtimes average doesn't
>>>> tell you the whole storey.
>>>> Also check your nodetool tpstats, are there a l
eads for my cluster which is on SSD.
>>> Can you also check the nodetool cfhistorgram, it tells you more about the
>>> number of SSTable involved and read/write latency. Somtimes average doesn't
>>> tell you the whole storey.
>>> Also check your nodetool
average
>> doesn't tell you the whole storey.
>> Also check your nodetool tpstats, are there a lot dropped reads?
>>
>> -Wei
>> - Original Message -
>> From: "Jon Scarborough"
>> To: user@cassandra.apache.org
>> Sent: Friday, M
: High disk I/O during reads
Checked tpstats, there are very few dropped messages.
Checked histograms. Mostly nothing surprising. The vast majority of rows are
small, and most reads only access one or two SSTables.
What I did discover is that of our 5 nodes, one is performing well, with disk
I/O
h"
> To: user@cassandra.apache.org
> Sent: Friday, March 22, 2013 9:42:34 AM
> Subject: Re: High disk I/O during reads
>
> Key distribution across probably varies a lot from row to row in our case.
> Most reads would probably only need to look at a few SSTables, a few mig
doesn't tell you the
whole storey.
Also check your nodetool tpstats, are there a lot dropped reads?
-Wei
- Original Message -
From: "Jon Scarborough"
To: user@cassandra.apache.org
Sent: Friday, March 22, 2013 9:42:34 AM
Subject: Re: High disk I/O during reads
Key distribution
ache.org<mailto:user@cassandra.apache.org>>
> Date: Friday, March 22, 2013 8:38 AM
> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Subject: RE: High disk I/O during reads
&
apache.org
Subject: Re: High disk I/O during reads
Did you mean to ask "are 'all' your keys spread across all SSTables"? I am
guessing at your intention.
I mean I would very well hope my keys are spread across all sstables or
otherwise that sstable should not be there as he has
38 AM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>"
mailto:user@cassandra.apache.org>>
Subject: RE: High disk I/O during reads
Are your Keys spread across all SSTables ? That will cause every sstable read
which will increase the I/O.
What compaction are
: High disk I/O during reads
Hello,
We've had a 5-node C* cluster (version 1.1.0) running for several months. Up
until now we've mostly been writing data, but now we're starting to service
more read traffic. We're seeing far more disk I/O to service these reads than
I would ha
Hello,
We've had a 5-node C* cluster (version 1.1.0) running for several months.
Up until now we've mostly been writing data, but now we're starting to
service more read traffic. We're seeing far more disk I/O to service these
reads than I would have anticipated.
The CF being queried consists of
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