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Posted to user@cassandra.apache.org by kannan chandrasekaran <ck...@yahoo.com> on 2010/10/07 20:19:56 UTC
Heap Settings suggestions
>From the Cassandra documentation @ riptano I see the following recommendation
for Heap size setting
MemtableThroughputInMB * 3 * (number of ColumnFamilies) + 1G + (size of internal
caches)
What if there is more than one keyspace in the system ? Assuming each keyspace
has the same number of column families, Can I linearly scale the above
recommendation to the number of keyspaces in the system .ie, if the "X" is the
heap size for a single keyspace and there are "Y" keyspaces, Is it recommended
to allocate "XY" as the max Heap size ? Please let me know.
Thanks
Kannan
PS: Thanks a lot for the documentation and recommendations.
Re: Heap Settings suggestions
Posted by kannan chandrasekaran <ck...@yahoo.com>.
Good point..
Thanks to both of you for the replies.
Kannan
________________________________
From: Matthew Dennis <md...@riptano.com>
To: user@cassandra.apache.org
Sent: Thu, October 7, 2010 4:59:28 PM
Subject: Re: Heap Settings suggestions
Keep in mind that .7 and on will have per-CF settings for most things so there
will be even more control over the the tuning...
On Oct 7, 2010 3:10 PM, "Peter Schuller" <pe...@infidyne.com> wrote:
>> What if there is more than one keyspace in the system ? Assuming each
>> keyspace has the same number of column families, Can I linearly scale the
>> above recommendation to the number of keyspaces in the system .ie, if the
>> "X" is the heap size for a single keyspace and there are "Y" keyspaces, Is
>> it recommended to allocate "XY" as the max Heap size ? Please let me know.
>
> Yes. Each column family will have a memtable subject to the configured
> memory constraints; whether or not they are in different keyspaces
> does not matter.
>
> --
> / Peter Schuller
Re: Heap Settings suggestions
Posted by Matthew Dennis <md...@riptano.com>.
Keep in mind that .7 and on will have per-CF settings for most things so
there will be even more control over the the tuning...
On Oct 7, 2010 3:10 PM, "Peter Schuller" <pe...@infidyne.com>
wrote:
>> What if there is more than one keyspace in the system ? Assuming each
>> keyspace has the same number of column families, Can I linearly scale the
>> above recommendation to the number of keyspaces in the system .ie, if the
>> "X" is the heap size for a single keyspace and there are "Y" keyspaces,
Is
>> it recommended to allocate "XY" as the max Heap size ? Please let me
know.
>
> Yes. Each column family will have a memtable subject to the configured
> memory constraints; whether or not they are in different keyspaces
> does not matter.
>
> --
> / Peter Schuller
Re: Heap Settings suggestions
Posted by Peter Schuller <pe...@infidyne.com>.
> What if there is more than one keyspace in the system ? Assuming each
> keyspace has the same number of column families, Can I linearly scale the
> above recommendation to the number of keyspaces in the system .ie, if the
> "X" is the heap size for a single keyspace and there are "Y" keyspaces, Is
> it recommended to allocate "XY" as the max Heap size ? Please let me know.
Yes. Each column family will have a memtable subject to the configured
memory constraints; whether or not they are in different keyspaces
does not matter.
--
/ Peter Schuller