I am explaining it more. If your machine have 8 GB of memory. After reserving to Operating system and all other processes except tasktracker, you have 4 GB remaining(assume). The remaining process running is tasktracker. If the child jvm size is 200 MB, Then you can define a maximum slots of 4*1024 MB/ 200 MB Which is approximately 20. You can divide the slots into mapper and reducer slots as per your requirement. This is just an example that I explained based on my knowledge.
On Thu, May 23, 2013 at 7:48 PM, <[EMAIL PROTECTED]> wrote:
> ** > Hi > > I assume the question is on how many slots. > > It dependents on > - the child/task jvm size and the available memory. > - available number of cores > > > > Your available memory for tasks is total memory - memory used for OS and > other services running on your box. > > Other services include non hadoop services as well as hadoop daemons. > > Divide the available memory with child jvm size and that would get the max > num of slots. > > Also check whether sufficient number of cores are available as well. > > > Regards > Bejoy KS > > Sent from remote device, Please excuse typos > ------------------------------ > *From: * Jitendra Yadav <[EMAIL PROTECTED]> > *Date: *Thu, 23 May 2013 18:10:38 +0530 > *To: *<[EMAIL PROTECTED]> > *ReplyTo: * [EMAIL PROTECTED] > *Subject: *Hadoop Installation Mappers setting > > Hi, > > While installing hadoop cluster, how we can calculate the exact number of > mappers value. > > > Thanks~ >
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