How to Troubleshoot Storage Performance in Vmware using Esxtop Command
Symptoms
1. First check the Server performance while accessing any file or folder if it’s normal then there is no issue with Storage to confirm…check the Storage log on the Esx Host in the VC..
2. While accessing file or folder if the server hung for 10-15 seconds then there is an issue on Disk I/O On the VM…
Steps to find out Lun issue on the Esxi using Esxstop command.
1. Log in to Esxi using Putty.
2. Run the command esxtop
To monitor storage performance on a per-LUN basis:
3.Start esxtop by typing esxtop from the command line.
4. Press u to switch to disk view (LUN mode).
5. Press f to modify the fields that are displayed.
6. Press b, c, f, and h to toggle the fields and press Enter.
7. Press s and then 2 to alter the update time to every 2 seconds and press Enter.
Maximum Threshold Value for Latency is 20 but we are getting 27-45 on Every 5 minutes.
To monitor storage performance on a per-virtual machine basis:
Start esxtop by typing esxtop at the command line.
Type v to switch to disk view (virtual machine mode).
Press f to modify the fields that are displayed.
Press b, d, e, h, and j to toggle the fields and press Enter.
Press s and then 2 to alter the update time to every 2 seconds and press Enter.
See Analyzing esxtop columns for a description of relevant columns.
Virtual Machine Performance on Storage.
The Latency value should not be more than 150 sec if it’s more than 350 or above seems to be issue with
Lun on the Datastore..
To monitor storage performance per HBA:
Start esxtop by typing esxtop at the command line.
Press d to switch to disk view (HBA mode).
To view the entire Device name, press SHIFT + L and enter 36 in Change the name field size.
Press f to modify the fields that are displayed.
Press b, c, d, e, h, and j to toggle the fields and press Enter.
Press s and then 2 to alter the update time to every 2 seconds and press Enter.
See Analyzing esxtop columns for a description of relevant columns.
Note:
If the Latency value more than recommended counter then there is issue with Connectivity with storage for Load balancing on Multipath
Solution
1. Log in to VC or Host using VI Client
2. Find the Datastore where the VM is configured.
3. Click the properties of the Datastore.
4. Check the multipath policy on the Datastore. Whether it’s fixed or MRU or RR…
To confirm check the other Datastore whether what policy is set
Provide the Target ID to storage team to confirm which one we need to set at Active I/O for disk performance on the HBA.
After confirmation from storage team which Target we need to select from Esxi…
Go to the storage and change the Target just right click and select preferred to the target.
So that Disk I/O will pass through the Target for further performance.
