Why do that? You reduce the cache effectiveness and up the logistical complexity. As a stopgap maybe, but not as a long term strategy.
Sun just needs to fix their GC. Er, Oracle. -ryan On Wed, Dec 15, 2010 at 11:55 AM, Chad Walters <chad.walt...@microsoft.com> wrote: > Why not run multiple JVMs per machine? > > Chad > > -----Original Message----- > From: Ryan Rawson [mailto:ryano...@gmail.com] > Sent: Wednesday, December 15, 2010 11:52 AM > To: dev@hbase.apache.org > Subject: Re: Hypertable claiming upto >900% random-read throughput vs HBase > > The malloc thing was pointing out that we have to contend with Xmx and GC. > So it makes it harder for us to maximally use all the available ram for block > cache in the regionserver. Which you may or may not want to do for > alternative reasons. At least with Xmx you can plan and control your > deployments, and you wont suffer from heap growth due to heap fragmentation. > > -ryan > > On Wed, Dec 15, 2010 at 11:49 AM, Todd Lipcon <t...@cloudera.com> wrote: >> On Wed, Dec 15, 2010 at 11:44 AM, Gaurav Sharma >> <gaurav.gs.sha...@gmail.com> wrote: >>> Thanks Ryan and Ted. I also think if they were using tcmalloc, it >>> would have given them a further advantage but as you said, not much >>> is known about the test source code. >> >> I think Hypertable does use tcmalloc or jemalloc (forget which) >> >> You may be interested in this thread from back in August: >> http://search-hadoop.com/m/pG6SM1xSP7r/hypertable&subj=Re+Finding+on+H >> Base+Hypertable+comparison >> >> -Todd >> >>> >>> On Wed, Dec 15, 2010 at 2:22 PM, Ryan Rawson <ryano...@gmail.com> wrote: >>> >>>> So if that is the case, I'm not sure how that is a fair test. One >>>> system reads from RAM, the other from disk. The results as expected. >>>> >>>> Why not test one system with SSDs and the other without? >>>> >>>> It's really hard to get apples/oranges comparison. Even if you are >>>> doing the same workloads on 2 diverse systems, you are not testing >>>> the code quality, you are testing overall systems and other issues. >>>> >>>> As G1 GC improves, I expect our ability to use larger and larger >>>> heaps would blunt the advantage of a C++ program using malloc. >>>> >>>> -ryan >>>> >>>> On Wed, Dec 15, 2010 at 11:15 AM, Ted Dunning >>>> <tdunn...@maprtech.com> >>>> wrote: >>>> > From the small comments I have heard, the RAM versus disk >>>> > difference is mostly what I have heard they were testing. >>>> > >>>> > On Wed, Dec 15, 2010 at 11:11 AM, Ryan Rawson <ryano...@gmail.com> >>>> wrote: >>>> > >>>> >> We dont have the test source code, so it isnt very objective. >>>> >> However I believe there are 2 things which help them: >>>> >> - They are able to harness larger amounts of RAM, so they are >>>> >> really just testing that vs HBase >>>> >> >>>> > >>>> >>> >> >> >> >> -- >> Todd Lipcon >> Software Engineer, Cloudera >> > >
