by lunarg on August 19th 2016, at 16:17

Found this interesting read on VMFS Extents and some of the (negative) myths that have arisen over the years:

by lunarg on August 16th 2016, at 14:30
Like private IP address ranges (defined in RFC 1918), there are also private MAC address ranges. These are called Locally Administered Address Ranges which are never used by devices or other vendors. MAC addresses in these ranges can be safely used, assuming they are unique within your network:





The ranges may seem odd but is explained best by this excerpt from Wikipedia:

Universally administered and locally administered addresses are distinguished by setting the second least significant bit of the most significant byte of the address. If the bit is 0, the address is universally administered. If it is 1, the address  ...
by lunarg on August 10th 2016, at 15:31
It may not seem evident to find out which mailboxes are accessible by a particular user or group. Through EAC, there is no apparent way to do this, as giving access for a user to a (shared) mailbox can only be done through the shared mailbox and then providing the user/group access. There is no way to query a particular user/group and show a list of mailboxes that user/group has access to. Fortunately, it seems that Powershell (EMS) does provide an easier answer.

These cmdlets work in both Office365 and on-premise Exchange 2007 or newer.

List mailboxes to which a user/group has access to:

Get-Mailbox | Get-MailboxPermission -User user1

Although the cmdlet states a user name, replacing th  ...
by lunarg on August 8th 2016, at 16:10
Microsoft has disabled the F8 key so you can no longer boot Windows 10 in Safe Mode right after powering on your computer. Safe Mode (although it's no longer called that) is still available but is only accessible if you explicitly asks for it when running Windows (there are plenty of articles that explain how this works). Windows 10 also has a mechanism for detecting boot problems and will automatically start in Safe Mode if normal startup is no longer possible. But what if you're not able to start Windows 10 the normal way, and the detection mechanism doesn't work? You can then opt to boot using a Recovery Drive (can be a DVD or USB stick). Or, you can simply re-enable the F8 key... (needs   ...
by lunarg on August 8th 2016, at 12:31
When performing a backup using VSS, a warning is logged in the Application event log of Windows with ID 8230 while taking the VSS snapshot. The backup may subsequently fail.

The warning states:

Volume Shadow Copy Service error: Failed resolving account Administrator with status 1376. Check connection to domain controller and VssAccessControl registry key. Operation: PrepareForSnapshot EventContext: Execution Context: Writer Writer Class Id: {afbab4a2-367d-4d15-a586-71dbb18f8485} Writer Name: Registry Writer Writer Instance ID: {0c8f797c-42cb-410d-a2c3-2877a6c93e38}Error-specific details: Error: NetLocalGroupGetMemebers(Administrator), 0x80070560, The specified local group does   ...
by lunarg on August 4th 2016, at 17:25
Backup of a SQL Server may fail with a VSS error.

From the log, the following message can be found:

One or more errors occurred. ---> Replay.Core.Contracts.Transfer.VssGeneralErrorException: There was a problem with the VSS subsystem on '(agent-machine)l'. ---> Replay.Agent.Contracts.ShadowCopy.ShadowCopyWriterFailedException: The VSS writer 'SqlServerWriter' failed during the 'DoSnapshotSet' phase with error WriterErrorNonRetryable. The VSS writer state is FailedAtPrepareSnapshot ---> Replay.Common.Contracts.ReplayException

In the Application event log on the machine, event 8229 is logged:

Event 8229
A VSS writer has rejected an event with error 0x800423f4, The writer experienc  ...
by lunarg on August 4th 2016, at 10:57

Using ADUC, it can be quite a hassle to find and/or unlock AD accounts. Powershell solves this by providing some neat commands for a system administrator to use.

To list all locked out AD accounts:

Search-ADAccount -LockedOut

To get more info about these accounts, you can do a Full-List:

Search-ADAccount -LockedOut | FL

Furthermore, you can pipe the output to quickly unlock some/all AD accounts:

Search-ADAccount -LockedOut | Unlock-ADAccount
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