Steady writes to SSD, dtrace/rwbypid.d not working on 10.8 ?

Discussion in 'OS X Mountain Lion (10.8)' started by paulCC, Jun 19, 2013.

  1. paulCC, Jun 19, 2013
    Last edited: Jun 19, 2013

    paulCC macrumors member

    Nov 2, 2012
    I was lucky enough to be able to switch to a new SSD - the Crucial M500/960GB, this on an 2011 15 Early Macbook Pro.

    As this is my first SSD, it looked up all the needed tweaks for SSD, implemented the ones that makes sense ( TRIM, SmartSleep, no access time flag, etc... )

    In the process I noticed that there is a steady stream of write I/O to the SSD. After some 30 hours, Activity monitor shows 15GB read, and 32GB written. That seems to be strange.

    I used iotop to see some of the writes - but this gives a snapshot, while I'd like a summary after some longer period of time. For this, Google says uses rwbypid.d or bitesize.d.

    The problem is that these do not seem to work. When I terminate them via CTRL-C, they just exit, but do not print any collected stats. Am I wrong in expecting them to print the stats on exit ?

    In addition - are there any other tools to get per/process disk I/O statistics ?

    Thanks for any info. Paul.
  2. crjackson2134 macrumors 68040


    Mar 6, 2013
    Charlotte, NC
    Not sure about some parts of your question, but have you checked to make site TimeMachine is turns OFF?

    Also, if this is a new drive, it could be indexing.

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