I think -server and -d64 are actually mutually exclusive and -d64 has priority. It's also worth considering whether you should look into this more deeply as well. Exactly as Demian mentioned there can be big differences between JVM builds and the flags they choose to set by default. Most typically they show up across different OS's.

Our experience on Solaris for example was that switching on -d64 cause the amount of RAM required to do the same job bloated considerably because of the way the JVM instantly became more generous with things like per-thread stack allocations. Flags like -XX:+UseCompressedOops -Xss64k start to become helpful after turning on -d64... if relevant to your JVM.

In the end we setup a spreadsheet and tested the impact of a lot of different settings, then implicitly set flags for them (even if they were the default). We managed to halve both our indexing time and RAM consumption. Not to mention that Solrmarc could do with some considerable optimizations. We shaved around 20% of the load out of there too iirc.

Ta,
Greg

On 31 January 2012 22:45, Demian Katz <demian.katz@villanova.edu> wrote:
Apparently it depends on which build of the JDK you use -- the -d64/-d32 switches are only necessary for builds that are compiled to support either 32-bit or 64-bit architecture.  If it's a 64-bit-only build, you don't need to specify.  Also, it appears that the -server switch is implicit when -d64 mode is set, so that would explain why you don't need that either.

- Demian
________________________________________
From: Alan Rykhus [alan.rykhus@mnsu.edu]
Sent: Monday, January 30, 2012 4:57 PM
To: vufind-tech@lists.sourceforge.net
Subject: Re: [VuFind-Tech] Questions re: moving from 32 bit OS to 64 bit OS

Hello,

I take it these suggestions are only if you run the Sun JDK? Is this a
RHEL only suggestion and setting?

I'm asking because we run Ubuntu and OpenJDK. I use neither the -server
or -d64 flags without a problem and I allocate 8192m for memory.

al

On Mon, 2012-01-30 at 14:53 -0500, Spencer Lamm wrote:
> Thanks for the information!
>
>
> Spencer
>
> On Mon, Jan 30, 2012 at 1:27 PM, eoghan.ocarragain@gmail.com
> <eoghan.ocarragain@gmail.com> wrote:
>         Hi,
>         We use rhel 6  64bit & I don't remember any changes other than
>         the java_options -d64 switch.
>
>
>         There were a few SELinux issues during the install but nothing
>         64 bit specific as far as I remember.
>         Eoghan
>
>         Sent from my iPhone
>
>         On 30 Jan 2012, at 18:09, Spencer Lamm <slamm1@swarthmore.edu>
>         wrote:
>
>
>
>         > Hello Everyone,
>         > To address some performance issues related to the amount of
>         > memory we are able to allocate to JAVA heap we are going to
>         > be moving from a 32 bit RHEL6 server to a new server running
>         > 64bit RHEL6. From scanning documentation and listserv
>         > activity it looks like we will definitely need to go with
>         > the 64 bit JDK and set the -d64 flag when we allocate
>         > memory.
>         >
>         >
>         > Beyond those two considerations, is there anything else we
>         > need to address differently than we did with our 32-bit
>         > install? Anything related to Apache, PHP, or MySQL?
>         >
>         >
>         > Also, if anybody has any experience with VuFind and RHEL6
>         > 64-bit and has some advice to pass along that would be
>         > great.
>         >
>         >
>         > Thank you!
>         > Spencer
>         >
>         >
>         > --
>         > Spencer Lamm
>         > Digital Initiatives Librarian
>         > Swarthmore College Library
>         > slamm1@swarthmore.edu
>         > 610-328-8541
>         >
>         >
>         >
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>
> --
> Spencer Lamm
> Digital Initiatives Librarian
> Swarthmore College Library
> slamm1@swarthmore.edu
> 610-328-8541
>
>
>
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--
Alan Rykhus
PALS, A Program of the Minnesota State Colleges and Universities
(507)389-1975
alan.rykhus@mnsu.edu
"It's hard to lead a cavalry charge if you think you look funny on a
horse" ~ Adlai Stevenson


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