vmware from split to monolithic disk


  1. Open a console to the ESXi host. For more information, see Using Tech Support Mode in ESXi 4.1 and ESXi 5.x (1017910).
  2. Run this command to load the multiextent module:

    # vmkload_mod multiextent
  3. Check if any of your virtual machine disks are of a hosted type. Hosted disks end with the -s00x.vmdk extension.
  4. Convert virtual disks in hosted format to one of the VMFS formats.

    To convert virtual disks in hosted format to one of the VMFS formats:

    1. Clone source hosted disk to a new disk using one of these commands:

      For a thick vmdk disk:

      • # vmkfstools -i VM-name.vmdk <VM-name-new-disk>.vmdk -d zeroedthick
      • # vmkfstools -i VM-name.vmdk /vmfs/volumes/destination_datastore/vmfolder/<VM-name-new-disk>.vmdk -d zeroedthick

      For a thin vmdkdisk:

      • # vmkfstools -i VM-name.vmdk <VM-name-new-disk>.vmdk -d thin
      • # vmkfstools -i VM-name.vmdk /vmfs/volumes/destination_datastore/vmfolder/<VM-name-new-disk>.vmdk -d thin
    2. Delete the hosted disk after successful cloning using the command:

      # vmkfstools -U VM-name.vmdk


ksim generic wait event

Bug 16921832  Very high "ksim generic wait event" from parallel query in a RAC environment

 This note gives a brief overview of bug 16921832. 
 The content was last updated on: 08-FEB-2015
 Click here for details of each of the sections below.


Product (Component)Oracle Server (Rdbms)
Range of versions believed to be affectedVersions BELOW 12.2
Versions confirmed as being affected
Platforms affectedGeneric (all / most platforms affected)


The fix for 16921832 is first included in

Interim patches may be available for earlier versions - click here to check.


Related To:


This bug is only relevant when using Real Application Clusters (RAC) and Parallel Query (PQO)
Very high "ksim generic wait event" may be seen when using parallel query in a RAC 
environment with auto DOP. Also OCSSD may use high CPU.
Rediscovery Notes
  If the system is RAC
  parallel query is used with automatic degree of parallelism
  many sessions are seen to wait for "ksim generic wait event" 
  then this bug may be suspected.
  OCSSD keeps reporting 'clssgmGroupState: requested group state of unknown group'
  If an interim patch for 16554552 has been installed then an ORA-7445 [kjuinc] 
  might be seen with kxfpRefreshInst on the stack. This fix should be used in place of that fix.
  Setting parallel_force_local=true can help avoid this issue.



"Din cinci oameni din București, doi sunt nebuni și doi sunt pe cale să devină nebuni. Eu sunt undeva între ăia patru."


R and big data

When most people think about analytics and Hadoop, they tend to think of technologies such as Hive, Pig and Impala as the main tools a data analyst uses. When you talk to data analysts and data scientists though, they’ll usually tell you that their primary tool when working on Hadoop and big data sources is in fact “R”, the open-source statistical and modelling language “inspired” by SAS but now with its own rich ecosystem, and particularly suited to the data preparation, data analysis and data correlation tasks you’ll often do on a big data project