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From Kanwar Sangha <kan...@mavenir.com>
Subject RE: Hinted handoff
Date Thu, 07 Mar 2013 12:59:29 GMT
<Do you have 9.5TB on a single node ?>
In the normal case it's best to have around 300 to 500GB per node. With that much data is
will take a week to run repair or replace a failed node.

Hi Aaron - This was true for pre 1.2 but with 1.2 and virtual nodes, does this still hold
? 1 TB at 1Gb/s will take roughly 2.2hrs assume we stream from say 100 nodes...


From: aaron morton [mailto:aaron@thelastpickle.com]
Sent: 06 March 2013 23:47
To: user@cassandra.apache.org
Subject: Re: Hinted handoff

Check the IO utilisation using iostat

You *really* should not need to make HH run faster, if you do there is some thing bad going
on. I would consider dropping the hints and running repair.

Data is ~9.5 TB
Do you have 9.5TB on a single node ?
In the normal case it's best to have around 300 to 500GB per node. With that much data is
will take a week to run repair or replace a failed node.

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 6/03/2013, at 1:22 PM, Kanwar Sangha <kanwar@mavenir.com<mailto:kanwar@mavenir.com>>
wrote:


Is this correct ?

I have Raid 0 setup for 16 TB across 8 disks. Each disk is 7.2kRPM with IOPS of 80 per disk.
Data is ~9.5 TB

So 4K * 80 * 9.5 = 3040 KB ~  23.75 Mb/s.

So basically I am limited at the disk rather than the n/w

From: Kanwar Sangha [mailto:kanwar@mavenir.com<http://mavenir.com>]
Sent: 06 March 2013 15:11
To: user@cassandra.apache.org<mailto:user@cassandra.apache.org>
Subject: RE: Hinted handoff

After trying to bump up the "hinted_handoff_throttle_in_kb" to 1G/b per sec, It still does
not go above 25Mb/s.  Is there a limitation ?



From: Kanwar Sangha [mailto:kanwar@mavenir.com]
Sent: 06 March 2013 14:41
To: user@cassandra.apache.org<mailto:user@cassandra.apache.org>
Subject: RE: Hinted handoff

Got the param. thanks

From: Kanwar Sangha [mailto:kanwar@mavenir.com]
Sent: 06 March 2013 13:50
To: user@cassandra.apache.org<mailto:user@cassandra.apache.org>
Subject: Hinted handoff

Hi - Is there a way to increase the hinted handoff throughput ? I am seeing around 8Mb/s (bits).

Thanks,
Kanwar


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