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From: Oleg Anastasyev <oleganas@gmail.com>
Subject: Re: Native heap leaks?
Date: Thu, 5 May 2011 06:37:48 +0000 (UTC)
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Probably this is because of mmapped io access mode, which is enabled by default
in 64-bit VMs - RAM is occupied by data files.
If you have such a tight memory reqs, you can turn on standard access mode in
storage-conf.xml, but dont expect it to work fast then:
<!--                                                                           
                                                                               
         
  ~ Access mode.  mmapped i/o is substantially faster, but only practical on   
                                                                               
          
  ~ a 64bit machine (which notably does not include EC2 "small" instances)     
                                                                               
          
  ~ or relatively small datasets.  "auto", the safe choice, will enable        
                                                                               
          
  ~ mmapping on a 64bit JVM.  Other values are "mmap", "mmap_index_only"       
                                                                               
          
  ~ (which may allow you to get part of the benefits of mmap on a 32bit        
                                                                               
          
  ~ machine by mmapping only index files) and "standard".                      
                                                                               
          
  ~ (The buffer size settings that follow only apply to standard,              
                                                                               
          
  ~ non-mmapped i/o.)                                                          
                                                                               
          
  -->                                                                          
                                                                               
          
 <DiskAccessMode>standard</DiskAccessMode>