Re: JNA + Cassandra security

2012-05-01 Thread Rob Coli
On Mon, Apr 30, 2012 at 6:48 PM, Jonathan Ellis  wrote:
> On Mon, Apr 30, 2012 at 7:49 PM, Cord MacLeod  wrote:
>> Hello group,
>>
>> I'm a new Cassandra and Java user so I'm still trying to get my head around 
>> a few things.  If you've disabled swap on a machine what is the reason to 
>> use JNA?
>
> Faster snapshots, giving hints to the page cache with fadvise.

If you are running in Linux, you really do want this enabled.
Otherwise, for example, compaction blows out your page cache.

(FWIW, in case it is not immediately apparent what sort of hints
Cassandra might give to the page cache with fadvise..)

https://issues.apache.org/jira/browse/CASSANDRA-1470

=Rob

-- 
=Robert Coli
AIM>ALK - rc...@palominodb.com
YAHOO - rcoli.palominob
SKYPE - rcoli_palominodb


Re: JNA + Cassandra security

2012-04-30 Thread Jonathan Ellis
On Mon, Apr 30, 2012 at 7:49 PM, Cord MacLeod  wrote:
> Hello group,
>
> I'm a new Cassandra and Java user so I'm still trying to get my head around a 
> few things.  If you've disabled swap on a machine what is the reason to use 
> JNA?

Faster snapshots, giving hints to the page cache with fadvise.

>  A second question is doesn't JNA break the Java inherent security mechanisms 
> by allowing access to direct system calls outside of the JVM?  Are there any 
> concerns around this?

We're not trying to sandbox anything here; there's lots of places
where we explicitly allow arbitrary Java code to be injected into
Cassandra.  You don't need native code to do dangerous things with
that!

-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com


Re: JNA + Cassandra security

2012-04-30 Thread aaron morton
> If you've disabled swap on a machine what is the reason to use JNA?
JNA will still be used to efficiently make hard links for snapshots. It's not 
necessary to lock the JVM memory when swap is disabled. 

> A second question is doesn't JNA break the Java inherent security mechanisms 
> by allowing access to direct system calls outside of the JVM?  Are there any 
> concerns around this?

Anyone else have an answer? 

Cheers

-
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 1/05/2012, at 12:49 PM, Cord MacLeod wrote:

> Hello group,
> 
> I'm a new Cassandra and Java user so I'm still trying to get my head around a 
> few things.  If you've disabled swap on a machine what is the reason to use 
> JNA?  A second question is doesn't JNA break the Java inherent security 
> mechanisms by allowing access to direct system calls outside of the JVM?  Are 
> there any concerns around this?



JNA + Cassandra security

2012-04-30 Thread Cord MacLeod
Hello group,

I'm a new Cassandra and Java user so I'm still trying to get my head around a 
few things.  If you've disabled swap on a machine what is the reason to use 
JNA?  A second question is doesn't JNA break the Java inherent security 
mechanisms by allowing access to direct system calls outside of the JVM?  Are 
there any concerns around this?