All Flash Disks showing as HDD in vSAN 6 - Full vSAN Datastore

[baabak_banyahma]

I have built my lab vSAN6 and added the nested ESXi hosts to it.  the disks are showing as Flash (enabled SSD and capcacity flash enabled) but when I add them to vSAN cluster and try to create the disk groups showing up as regular HDD (screenshots)

How do I get vSAN to recognize the disks as flash(SSD)

[CHogan]

Expected behaviour - VSAN 6.0 Part 4 – All-Flash VSAN Capacity Tier Considerations | CormacHogan.com

I agree that its a bit misleading.

[baabak_banyahma]

I agree but still even though the SSD=1 and IsCapacityFlash=1, vSAN does not see any of the setting, so cannot create any disk group.

any work around?

[CHogan]

One device should be left as cache (ie do not mark as capacity).

Then you will have an SSD for cache and an SSD for capacity, allowing you to create a disk group

[ramakrishnak · Accepted solution]

From the beginning of the vsan sofware, we introduced diskgroup concept

where a diskgroup consists of flash tier and capacity tier. flash tier was SSD and capacity tier HDD in hybrid cases

To keep this consistent and simpler for all flash, we introduced the notion of promoting additional SSDs to capacity tier. but still the original requirement of having 1 SSD assigned for flash tier is a must

so what you have to do in your case is

keep 1 SSD for flash  tier without promoting them to capacity tier. you can remove the satp rule

use esxcli vsan storage tag to remove the capacityFlash for one of the SSD disk (as mentioned in cormac's link)

that will fix your setup

[baabak_banyahma]

Cormac, I need your help again.  I have added 1 flash and 2 HDD to the vSAN and it shows as 415 GB free space under vsan setting but "vsandatastore" shows as full.  I added the 100 GB disks and the capacity used grow.  I have not deployed anything on this datastore.

what am I missing here?

[CHogan]

Were the disks used for VSAN before?

If so, delete the disk groups completely from VSAN via the UI, then recreate them.

This should delete any residual information left on the disks.

[baabak_banyahma]

I deleted the disk groups and re-created them, same result.  I even deleted the ESXi disks (being virtual host) and added new disks and re-created the disk groups, still got the same result

on the vSAN cluster, it gets me 400+ GB free space but on vSAN datastore, I will only get 39 GB free space.

[ramakrishnak]

can you check what do you see

vsanDatastore view -> Manage -> settings -> General -> Under Capacity (total capacity|Provisioned space| free space)

also under

vsanDatastore view -> Manage -> files -> VsanDatastore. do you see any files|dir residing ?

if not, then you might want to look at the rvc cmd output, run from logging into vCenter and after connecting to rvc

> vsan.disks_stats <clustername>

> vsan.check_state <clustername>

if this doesn't give any clues, i would suggest collect vc-support/vm-support bundles and file an SR so we can root-cause the issue you are facing

Thanks,