M4T
Enthusiast
Enthusiast

System Logs vSAN

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Hi community,

I've never had so much trouble trying to set up a vSAN before all flash. but I've had issue after issue for the last 3 days, I was wondering if someome could help with regards to performance statistics in vSAN wont show up it says in the health side performance service not enabled but yet it is but no data shows up and on each host it says system logs are stored on non persistent storage ive tried to change the path in the advanced settings like I did before but for some reason this all flash vsan doesn't want to change the settings and it just shows a error all the time saying "a specific parameter was not correct" it worked before where on the vsan storage I created a folder called "logs" and used that it worked perfectly fine but for some reason this all flash vsan doesn't want to do that? also on the vsan cluster view under vsan I have a error that says " stats master cannot be found" im guessing that's because their isn't any logs set up on the two hosts?

matt

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TheBobkin
VMware Employee
VMware Employee

Hello Matt,

" it worked before where on the vsan storage I created a folder called "logs" and used that it worked perfectly fine but for some reason this all flash vsan doesn't want to do that?"

Don't log to vsanDatastore - it's not supported and can cause severe issues on your host/cluster:

VMware Knowledge Base

Also, as I said on your other question - having logging configured to a location can prevent that datastore from being removed properly and/or referenced.

"also on the vsan cluster view under vsan I have a error that says " stats master cannot be found" im guessing that's because their isn't any logs set up on the two hosts?"

Where logging is located should have no bearing on Performance service as these data are stored in the stats.db Object.

Thus it sounds like you have 2 issues - the stats Object being non-functional or inaccessible can cause there to be no stats master (as no-one can write to the Object) - check the state of the Object:

Cluster > Monitor > vSAN > Health > Data  (and/or via the Performance Service configuration page)


Bob

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TheBobkin
VMware Employee
VMware Employee

Hello Matt,

" it worked before where on the vsan storage I created a folder called "logs" and used that it worked perfectly fine but for some reason this all flash vsan doesn't want to do that?"

Don't log to vsanDatastore - it's not supported and can cause severe issues on your host/cluster:

VMware Knowledge Base

Also, as I said on your other question - having logging configured to a location can prevent that datastore from being removed properly and/or referenced.

"also on the vsan cluster view under vsan I have a error that says " stats master cannot be found" im guessing that's because their isn't any logs set up on the two hosts?"

Where logging is located should have no bearing on Performance service as these data are stored in the stats.db Object.

Thus it sounds like you have 2 issues - the stats Object being non-functional or inaccessible can cause there to be no stats master (as no-one can write to the Object) - check the state of the Object:

Cluster > Monitor > vSAN > Health > Data  (and/or via the Performance Service configuration page)


Bob

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M4T
Enthusiast
Enthusiast

hi bob,

- can I use anything to store the logs on in the vsan? as there arnet any more spaces im assuming I cwould have to have a USB stick or some sort mounted to store them on?

- I have attached the image of the vSAN > Health > Data

pastedImage_0.png

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TheBobkin
VMware Employee
VMware Employee

Hello Matt,

You can use anywhere but vsanDatastore - if you don't have durable medium (e.g. only SD-card for boot) then you can't safely have persistent logging unless you can configure them somewhere else.

Options include any network-attached storage (e.g. NAS/iSCSI/FC), VMFS on a local disk, SATADOM or PCI-E storage device.

If by 'USB' you mean small storage stick then no, this is not durable and will burn out fast.

You have 1 Object and it is Healthy :smileygrin:, going to assume that is stats.db Object  - try disabling and re-enabling the Performance Service:

Cluster > Configure > vSAN > Health and Performance

If there is still no stats master elected then potentially you have some other issue with communication to host or services running properly, restart vsanmgmtd on all hosts and vmware-vsan-health service on the vCenter

All the commands and steps for these can be found here:

EMC Community Network - DECN: VxRail: VSAN health test fails on performance service check due to: St...

Bob

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M4T
Enthusiast
Enthusiast

hi bob,

I checked this morning on the system and it seems to have sorted itself out and everything is working now green everything lol so don't know what it did but it sorted it its self.

pastedImage_0.png

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