Hi All,
I have 2 hosts HA-DRS cluster, it seems that the DRS not work probably, when i look to the performance at 2 hosts, one of these hosts consume more memory 42 GB from 45 GB and the other one consume 26 GB of 45 GB, all of i know that the DRS balance the load on two host and automaticly migrate the VMs from one host to the other one,, but on my enviroment NOT ,,, any idea a bout this issue ???.
Well you could increase the migration threshold to max (which will directly impact the target load deviation) to enable DRS to vMotion off the VMs even for slight performance increase. Secondly, you can also look at this advanced setting to limit the no. of VMs per host, for vSphere 5.1 only:
http://www.yellow-bricks.com/2012/10/01/limit-the-amount-of-eggs-in-a-single-basket/
But I would not recommend any of the above actions unless your users are complaining about the performance. I would trust DRS to take the corrective if contention does arise.
do you have DRS setup as manual mode?
No, its fully automated mode .
No, DRS does not balance the workload. What DRS does is to migrate workloads in case of contention. It always does a cost-risk analysis before migrating VMs and if there's no need to do it, it won't generate any recommendations.
Here's an interesing blog post to read: http://www.yellow-bricks.com/drs-deepdive/
André
Thanks for your replay, in this case what shall i do du to the heavy load on one host and the other host engough memory to handle load ,,, please find my current DRS settings :
Migration Automation Level : Fully Automated .
Power Management : Off.
DRS Recomandation : 0.
DRS Faults : 0
Migration Thershold : Apply priority 1, Priority 2, and Priority 3 recommendations.
Target Host load standard deviation <`=0.2
Current Host load standard devition 0.074 (Load Balanced ) .
Should i change the Migration Thershold to do Migration ???? Please advise .
Any help will be appreciated .
Thanks in advance ,
Basem
What you've described can be a normal scenario in a VMware environment. Are you encountering performance issues of some sort? In a situation where the heavily utitlized host attempts to use more memory, one of several things can happen (none of which will normally cause a noticeable performance impact):
If this is still concerning, you could try manually vMotioning off of Host 1 to balance things out better.
Also, if you have HA enabled on this cluster, another concern might be if you have enough memory capacity for your HA to work effectively.
Let us know if this helps or if you have further questions.
Well you could increase the migration threshold to max (which will directly impact the target load deviation) to enable DRS to vMotion off the VMs even for slight performance increase. Secondly, you can also look at this advanced setting to limit the no. of VMs per host, for vSphere 5.1 only:
http://www.yellow-bricks.com/2012/10/01/limit-the-amount-of-eggs-in-a-single-basket/
But I would not recommend any of the above actions unless your users are complaining about the performance. I would trust DRS to take the corrective if contention does arise.
Maybe interesting to read: http://frankdenneman.nl/drs/drs-and-memory-balancing-in-non-overcomitted-clusters/
André
thanks for the links ![]()
