vSAN 5.5 U2 - Configuring Flash Read Cache getting error "Reason: an error occurred during host configuration"

[COS]

Hosts: DL360 G6, dual quad core, 64GB RAM

Drives: 3 SAS Spidles 10K RPM and 2 SSD's.

I'm trying to configure one of the hosts for Flash Read Cache but I get the ever so desciptive and helpless error message...

"Configuration on disk /vmfs/device/disks/naa.<longguid> Failed. Reason: an error occurred during host configuration"

I hope there is a log file I can check for a much deeper description of this lame error message.

Can anyone point me to where I can check on this error?

Thanks

[ramakrishnak]

Few things to check

a. check if the vsan storage providers are all registered and online for the vsan cluster hosts

    vc - > manage -> Storage providers section

b. check if home-> VM storage Policies  { create new storage policy rules sets shows up for VSAN } 

(if not then the vsan storage providers for that host is offline or not working. On corresponding host you can check for vsanvpd service and logs /var/log/vsanvpd.log)

c. to decipher the error in your case. look at the vpxd log on the cloudVM / VC side (/var/log/vmware/vpxd/ )

look at the /var/log/vpxa.log , /var/log/hostd.log (search for the same syntax on esx host side)

Thanks

[COS]

I haven't quite gotten to the point to configure vSAN datastores or enable it. Right now it's just a plain cluster with 3 hosts with local spindle datastores and SSD LUN's.

I was able to turn on the Flash Read Cache on the first and third hosts but the second one just will not work.

Thanks

[ramakrishnak · Accepted solution]

Oh. k. so this is vSphere Flash Read Cache (vFRC) feature and nothing to do with VSAN

check on the host logs which is throwing this error.

esp: /var/log/hostd.log and corresponding timeframe /var/log/vmkernel log. this will show what is going on here

you may want to check the following

a.

check whether the SSD LUNS are unused/ no other partition exists

# partedUtil getptbl /vmfs/devices/disks/<ssddisk>

b.

also check that the SSD lun on this host are local and eligible for vflash

# esxcli storage vflash device list

Thanks,

[COS]

Figured it out.

The partedutil showed there was a partition already.

So I booted to my bootable CD with disk utilities and blew away that partition.

Rebooted the host and all is well now.

This happened because this host already had an ESX build I was testing on. I thought that when I blew away the RAID sets that it killed the partition.

That wasn't the case. When the RAID set got recreated, it just used the same RAID data/info.

Anyway, the server is a DL360 G6 with the RAID controller P410i and I used the smart start CD to get to the ACU and build my RAID sets.

Thanks