RE: no change observed in read latency after switching from EBS to SSD storage

2014-09-18 Thread Mohammed Guller
To: user@cassandra.apache.orgmailto:user@cassandra.apache.org Subject: Re: no change observed in read latency after switching from EBS to SSD storage When you say you moved from EBS to SSD, do you mean the EBS HDD drives to EBS SSD drives? Or instance SSD drives? The m3.large only comes with 32GB

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-18 Thread Benedict Elliott Smith
:* Wednesday, September 17, 2014 7:17 PM *To:* user@cassandra.apache.org *Subject:* Re: no change observed in read latency after switching from EBS to SSD storage Read 193311 live and 0 tombstoned cells is your killer. returning 250k rows is a bit excessive, you should really page

RE: no change observed in read latency after switching from EBS to SSD storage

2014-09-18 Thread Mohammed Guller
@cassandra.apache.org Cc: Chris Lohfink Subject: Re: no change observed in read latency after switching from EBS to SSD storage It is possible this is CPU bound. In 2.1 we have optimised the comparison of clustering columns (CASSANDRA-5417https://issues.apache.org/jira/browse/CASSANDRA-5417), but in 2.0

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-17 Thread Alex Major
parameter in the cassandra.yaml file for large reads? Mohammed *From:* Robert Coli [mailto:rc...@eventbrite.com] *Sent:* Tuesday, September 16, 2014 5:42 PM *To:* user@cassandra.apache.org *Subject:* Re: no change observed in read latency after switching from EBS to SSD storage On Tue

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-17 Thread Robert Coli
On Tue, Sep 16, 2014 at 10:00 PM, Mohammed Guller moham...@glassbeam.com wrote: The 10 seconds latency that I gave earlier is from CQL tracing. Almost 5 seconds out of that was taken up by the “merge memtable and sstables” step. The remaining 5 seconds are from “read live and tombstoned

RE: no change observed in read latency after switching from EBS to SSD storage

2014-09-17 Thread Mohammed Guller
, September 17, 2014 3:47 AM To: user@cassandra.apache.org Subject: Re: no change observed in read latency after switching from EBS to SSD storage When you say you moved from EBS to SSD, do you mean the EBS HDD drives to EBS SSD drives? Or instance SSD drives? The m3.large only comes with 32GB

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-17 Thread Chris Lohfink
: Wednesday, September 17, 2014 3:47 AM To: user@cassandra.apache.org Subject: Re: no change observed in read latency after switching from EBS to SSD storage When you say you moved from EBS to SSD, do you mean the EBS HDD drives to EBS SSD drives? Or instance SSD drives? The m3.large only comes

no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Mohammed Guller
Hi - We are running Cassandra 2.0.5 on AWS on m3.large instances. These instances were using EBS for storage (I know it is not recommended). We replaced the EBS storage with SSDs. However, we didn't see any change in read latency. A query that took 10 seconds when data was stored on EBS still

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Robert Coli
On Tue, Sep 16, 2014 at 5:35 PM, Mohammed Guller moham...@glassbeam.com wrote: Does anyone have insight as to why we don't see any performance impact on the reads going from EBS to SSD? What does it say when you enable tracing on this CQL query? 10 seconds is a really long time to access

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread James Briggs
@cassandra.apache.org Sent: Tuesday, September 16, 2014 5:42 PM Subject: Re: no change observed in read latency after switching from EBS to SSD storage On Tue, Sep 16, 2014 at 5:35 PM, Mohammed Guller moham...@glassbeam.com wrote: Does anyone have insight as to why we don't see any performance impact

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Alex Kamil
. Mailbox dimensions: 10x12x14 -- *From:* Robert Coli rc...@eventbrite.com *To:* user@cassandra.apache.org user@cassandra.apache.org *Sent:* Tuesday, September 16, 2014 5:42 PM *Subject:* Re: no change observed in read latency after switching from EBS to SSD storage

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Tony Anecito
If you cached your tables or the database you may not see any difference at all. Regards, -Tony On Tuesday, September 16, 2014 6:36 PM, Mohammed Guller moham...@glassbeam.com wrote: Hi - We are running Cassandra 2.0.5 on AWS on m3.large instances. These instances were using EBS for

Re: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Ben Bromhead
EBS vs local SSD in terms of latency you are using ms as your unit of measurement. If your query runs for 10s you will not notice anything. What is a few less ms for the life of a 10 second query. To reiterate what Rob said. The query is probably slow because of your use case / data model, not

RE: no change observed in read latency after switching from EBS to SSD storage

2014-09-16 Thread Mohammed Guller
...@eventbrite.com] Sent: Tuesday, September 16, 2014 5:42 PM To: user@cassandra.apache.org Subject: Re: no change observed in read latency after switching from EBS to SSD storage On Tue, Sep 16, 2014 at 5:35 PM, Mohammed Guller moham...@glassbeam.commailto:moham...@glassbeam.com wrote: Does anyone have