hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Bryan Duxbury <br...@rapleaf.com>
Subject Re: re-balance regions based on avgLoad
Date Sun, 08 Jun 2008 03:19:11 GMT
We have an issue open tracking the fact that the rebalancing code has  
a tendency to oscillate. I haven't had the time to look at it for a  
while. It definitely needs some attention.

The point of checking whether the avgLoad is > 2.0 is to ensure that  
no rebalancing occurs before there are more regions than there are  
servers. It doesn't do anything in that case.

-Bryan

On Jun 7, 2008, at 7:55 PM, Rong-en Fan wrote:

> On Sun, Jun 8, 2008 at 10:53 AM, Rong-en Fan <grafan@gmail.com> wrote:
>> I'm playing with latest hbase trunk and noticed there is a
>> region close-then-assign looping.
>>
>> I have 3 region servers and total regions are about 108, and
>> the avgLoad is 36.0, then this code in RegionManager.java:
>>
>>      if (regionsToAssign.size() == 0) {
>>        // There are no regions waiting to be assigned. This is an  
>> opportunity
>>        // for us to check if this server is overloaded.
>>        double avgLoad = master.serverManager.getAverageLoad();
>>        if (avgLoad > 2.0 && thisServersLoad.getNumberOfRegions() >
 
>> avgLoad) {
>>
>> If I understand correctly, when there is no outstanding unassigned
>> regions, then RegionManager tries to check whether a region server
>> is overloaded by the # of loaded regions on this region server.
>> Then, it seems to me that avgLoad > 2.0 is quite unrealistic under
>> current calculation of "avgLoad".
>
> Forget to mention, under my situation, all 3 boxes are kicking regions
> among them as all loaded regions > avgLoad... even after assign
> some to others.
>
> Regards,
> Rong-En Fan
>
>> Isn't the better way to consider system load or based on # of loaded
>> regions and # of requests?
>>
>> Thanks,
>> Rong-En Fan
>>


Mime
View raw message