SqlServerWriter missing when Enable AlwaysOn Availability Groups

[Elpretension]

Hello together,

i have a problem with the SQL Server Writer and availability Groups.

I have a two node Failover Cluster with Availability Groups. The OS is Windows Server 2016 with Sql Server 2016, all System are up to date.
Two Instances are allready configured with 2 AG and everything is fine. SqlServerWriter is still running if i show it in Powershell with "VSSADMIN LIST WRITERS"

Now is the thing i dont unterstand. I have configured a third SQL Instance and want to use the Availability Groups.
For This i go to SQL Server Configuration Manager and mark the "Enable AlwaysOn Availability Groups" at this moment the "SQL Server Writer" dissapear and im not able to perform my backups anymore. Reinstall doenst help, at the same point the VSS Writer dissapear all the time.

If i delete the Instance or disable the Services of this Instance it appears again - Verry confused about that

I´m useing for each instance different Service Accounts

I´m think about an missings Securithy Right. But which one ? Any ideas ?

Thank you Guys!

[Dima P.]

Hello and welcome Elpretension.

Can you see any events related to VSS service in Windows event log after you add the third node to AON Group and VSS gets disabled? How you are backing up these nodes? Do you see any errors in backup job log? Thank you!

[Elpretension]

Hello Dima,

i´m Backing up with Veeam Backup & Replication 9.5.0.1536
Backup Warning:"SQL VSS Writer is missing: databases will be backed up in crash-consistent state and transaction log processing will be skipped"

For better understanding it´s not a third new Node i configure it on the two existing nodes where actually 2 Availabililty Groups are running fine.
I do not see anything unusal in Eventlog for VSS. Thats the following output for VSSADMIN List Writers

Code: Select all

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line to
(C) Copyright 2001-2013 Microsoft Corp.

Writer name: 'Task Scheduler Writer'
   Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124}
   Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b}
   State: [1] Stable
   Last error: No error

Writer name: 'VSS Metadata Store Writer'
   Writer Id: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06}
   Writer Instance Id: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93}
   State: [1] Stable
   Last error: No error

Writer name: 'Performance Counters Writer'
   Writer Id: {0bada1de-01a9-4625-8278-69e735f39dd2}
   Writer Instance Id: {f0086dda-9efc-47c5-8eb6-a944c3d09381}
   State: [1] Stable
   Last error: No error

Writer name: 'System Writer'
   Writer Id: {e8132975-6f93-4464-a53e-1050253ae220}
   Writer Instance Id: {d5495227-6cd8-4851-bbfb-1325c75cb332}
   State: [1] Stable
   Last error: No error

Writer name: 'Shadow Copy Optimization Writer'
   Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
   Writer Instance Id: {046ec9ca-de08-4bc4-8946-a6fcbf78b8bf}
   State: [1] Stable
   Last error: No error

Writer name: 'ASR Writer'
   Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4}
   Writer Instance Id: {8c57150e-042b-460e-b7e5-0936062dee75}
   State: [1] Stable
   Last error: No error

Writer name: 'Registry Writer'
   Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485}
   Writer Instance Id: {fa207bc2-29bc-42d6-b530-5459331c081d}
   State: [1] Stable
   Last error: No error

Writer name: 'COM+ REGDB Writer'
   Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f}
   Writer Instance Id: {0cdd35d6-83f8-4807-ae3e-0a45baeaa39a}
   State: [1] Stable
   Last error: No error

Writer name: 'Cluster Database'
   Writer Id: {41e12264-35d8-479b-8e5c-9b23d1dad37e}
   Writer Instance Id: {54544aec-c460-48c2-95e0-89c5e4272985}
   State: [1] Stable
   Last error: No error

Writer name: 'WMI Writer'
   Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0}
   Writer Instance Id: {484bcd46-b30b-4e6b-80c5-703b03e7453b}
   State: [1] Stable
   Last error: No error

Writer name: 'Cluster Shared Volume VSS Writer'
   Writer Id: {1072ae1c-e5a7-4ea1-9e4a-6f7964656570}
   Writer Instance Id: {e99da52a-9dba-41b9-ae07-5d264cd78e87}
   State: [1] Stable
   Last error: No error

The Writer Name just dissapears if i enable this Feature for the new Instance.

[Elpretension]

Guess i have some good news can localize the Failure maybe a bit

I´m having a look at Registry in HKLM\System\CurentControlSet\Services\VSS\Diag\SqlServerWriter

At the System it doesnt work i see just 4 entries and one with ((HRESULT)0x800426F46) (SetCurrentFailure)

GETSTATE(enter) and (leave) entries are missing in the System.

Maybe anyone now haveing a idea ?

[Dima P.]

Hi Elpretension.

EDIT: We had a quick discussion with QA. The general recommendation would be to open a case with MS support but we also think that system account might be missing from the sql administration group. Can you please check it? Thanks!

[Elpretension]

Thanks for Help Dima!

Is there any special Group wehere i need to add the System account ? I think the System account allreadys has these permissions.

Now i have synced the database from host 1 to host 2. At this moment the SQL Server writer failes again at the secondary Host. I think it is a permission failure in one Database but how i can find it ?!

[Elpretension]

Got it!

there was a Space at one mdf-File on filesystem. Everything works fine now!

[Dima P.]

So you are saying that renaming the mdf fixed the issue with VSS service? Good catch, thanks for sharing!