Hi,
I have 4 ESXi 5.1 server which has iSCSI storage mounted to it. In recent times i see many warning events in all 4 servers as "Device naa.xxxxxxxxxxxxxxxxxx performance has deteriorated. I/O latency increased from average value of 1659 microseconds to 168642 microseconds". These events occur on regular intervals for few minutes. I dont see any issues in my VM's during this time.
I also get the below mentioned events.
"Path redundancy to storage device naa.xxxxxxxxxxxxxxxxxx (Datastores: VOL0) restored. Path vmhba37:C1:T0:L0 is active again".
"Lost path redundancy to storage device naa.xxxxxxxxxxxxxxxxxx. Path vmhba37:C1:T0:L0 is down. Affected datastores: VOL0".
When i contacted my storage vendor he told it has to be checked on ESXi server side.
Can some one let me know what does these events mean?Thanks in advance...
Well, I am afraid it is going to be a big chase now for you. You will know later ![]()
Check this kb from VMware
Like you said, that the VMs are running fine, it is just the messages which VMware algorithm treats for calculation or finding out the time of max/min load. These can be ignored, if you find no issues in the VM performance.
Its the counters which VMware has gathered the performance data from the storage side, you could take a look at the storage counters to fix this issue here.
The first one indicates that the response time of your storage system / datastores is much to high (which can be normal, if some of your VMs sending a lot of IO for example). There can be many reasons for this, eg.: The affected datastore is under contention / huge I/O load, you have some performance problems within your network (regarding you are using iSCSI) etc.
The second message shows that a path to your storage system was totaly unreachable for a moment, which of course can be related to the first error.
Overall there can be many reasons for this problems. I would suggest you to start with checking the iSCSI network.
Regards,
Mario
Thanks for your reply guys... I went through the kb. I monitored my switch today and did not find any disconnection... I also contacted my storage vendor again and he has suggested to upgrade the firmware and am planning to do it this weekend.
