John's questions

I have a MySQL database server, db.t3.micro, parameter group is 'default.mysql8.0', max_connections is '{DBInstanceClassMemory/12582880}'

I figured out that it cannot handle more than ~63 connections

According to AWS RDS documentation https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Limits.html#RDS_Limits.MaxConnections

Connection limit for Mysql is calculated using '{DBInstanceClassMemory/12582880}' formula, where DBInstanceClassMemory tier instance memory in bytes.

So for db.t3.micro 1Gb it is 1073741824/12582880 = 85

‘SHOW VARIABLES LIKE "max_connections";’ returns 63

Why real connections limit is less than the formula result?

that should be simple, but I cannot figure that out

Amazon bills the real used storage amount for Aurora databases, not the allocated storage like for non-Aurora.

there is a metric VolumeBytesUsed - The amount of storage used by your Aurora DB instance. This metric applies to an entire Aurora DB cluster, not for instance. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Monitoring.html

I have a cluster of 1 Arora Writer and 2 Readers. DB size is about 10 Gb and VolumeBytesUsed shows 10Gb. According to documentation, each Aurora node has its own data copy - https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Aurora.Overview.html So if I have 10Gb DB - Aurora Writer and 2 Readers should be using 10x3 = 30 Gb of storage, but VolumeBytesUsed shows 10Gb

Will I be billed for 10 Gb or 30 Gb in that case?

I was able to create a dedicated t3a instance in EC2 console.

But I have not found any mention of t3a here, only t3 https://aws.amazon.com/ec2/pricing/dedicated-instances/

Does t3a support dedicated? How to verify that my VM is dedicated?

UPD1. Here is a tenancy option I spcified - "Dedicated - Run a Dedicated instance"

Im trying to query MSFT classes under non-admin user

Windows PowerShell Copyright (C) 2014 Microsoft Corporation. All rights reserved.

PS C:\Users\john.doe> Get-WmiObject -Query "SELECT * FROM MSFT_Disk" 
-Namespace Root/Microsoft/Windows/Storage Get-WmiObject : Access denied At line:1 char:1
+ Get-WmiObject -Query "SELECT * FROM MSFT_Disk"  -Namespace Root/Microsoft/Window ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [Get-WmiObject], ManagementException
    + FullyQualifiedErrorId : GetWMIManagementException,Microsoft.PowerShell.Commands.GetWmiObjectCommand

PS C:\Users\john.doe>

1. I did all the steps mentioned in Which permissions/rights does a user need to have WMI access on remote machines? answer.

2. I can query other namespaces like CIMv2

3. I verified that 'Root/Microsoft/Windows/Storage' namespace security has all the checkboxes set for john.doe user (domain user)

It looks like Root/Microsoft/Windows/* namespace requires some additional permissions (I get access denied for MSFT_SmbConnection too for example) but I cannot figure out what permissions

Im getting some strange results for Msft_Volume query

Get-WmiObject -Query "SELECT * FROM Msft_Volume"  -Namespace Root/Microsoft/Windows/Storage

I see 'D' drive six times! I there any explanation and which one is real?

AllocationUnitSize   : 4096
DedupMode            : 4
DriveLetter          : D
DriveType            : 3
FileSystem           : NTFS
FileSystemLabel      : DATA
FileSystemType       : 14
HealthStatus         : 0
ObjectId             : {1}\\DELLCSPRHV02\root/Microsoft/Windows/Storage/Providers_v2\WSP_Volume.ObjectId="{60fd5c97-6507-4543-99f1-daf47227f21e}:VO:\\?\Volume{0074c0a4-0000-0000-0000-100000000000}\"
OperationalStatus    : {2}
PassThroughClass     :
PassThroughIds       :
PassThroughNamespace :
PassThroughServer    :
Path                 : \\?\Volume{0074c0a4-0000-0000-0000-100000000000}\
Size                 : 162522984448
SizeRemaining        : 48756031488
UniqueId             : \\?\Volume{0074c0a4-0000-0000-0000-100000000000}\
PSComputerName       : DELL590HV12



AllocationUnitSize   : 4096
DedupMode            : 4
DriveLetter          : D
DriveType            : 3
FileSystem           : NTFS
FileSystemLabel      : DATA
FileSystemType       : 14
HealthStatus         : 0
ObjectId             : {1}\\DELLCSPRHV02\root/Microsoft/Windows/Storage/Providers_v2\WSP_Volume.ObjectId="{60fd5c97-6507-4543-99f1-daf47227f21e}:VO:\\?\Volume{2d4b4fad-0000-0000-0000-100000000000}\"
OperationalStatus    : {2}
PassThroughClass     :
PassThroughIds       :
PassThroughNamespace :
PassThroughServer    :
Path                 : \\?\Volume{2d4b4fad-0000-0000-0000-100000000000}\
Size                 : 162522984448
SizeRemaining        : 128554635264
UniqueId             : \\?\Volume{2d4b4fad-0000-0000-0000-100000000000}\
PSComputerName       : DELL590HV12



AllocationUnitSize   : 4096
DedupMode            : 4
DriveLetter          : D
DriveType            : 3
FileSystem           : NTFS
FileSystemLabel      : DATA
FileSystemType       : 14
HealthStatus         : 0
ObjectId             : {1}\\DELLCSPRHV02\root/Microsoft/Windows/Storage/Providers_v2\WSP_Volume.ObjectId="{60fd5c97-6507-4543-99f1-daf47227f21e}:VO:\\?\Volume{4491b922-0000-0000-0000-100000000000}\"
OperationalStatus    : {2}
PassThroughClass     :
PassThroughIds       :
PassThroughNamespace :
PassThroughServer    :
Path                 : \\?\Volume{4491b922-0000-0000-0000-100000000000}\
Size                 : 162522984448
SizeRemaining        : 50788323328
UniqueId             : \\?\Volume{4491b922-0000-0000-0000-100000000000}\
PSComputerName       : DELL590HV12

full output: https://pastebin.com/qRiCEUL3

There are no spanned volumes.

The sum of all SizeRemaining = 535GB

The only second disk has correct SizeRemaining

Size                 : 162522984448
SizeRemaining        : 128554635264
128554635264/(1024*1024*1024) = 119.725833892822 Gb

I made some changes to HyperV host SMBIOS that caused host UUID change.

The problem that in VMM I still see old host UUID (in host properties and in Get-SCVMHost). I tried to restart VMM service and VMM agent, I tried to refresh host and cluster - UUID still wrong.

Is there any way to re-sync VMM with the host so host UUID will be updated?

I have ran CPU stress test on linux HyperV VM. Linux reports 100% CPU utilization, but "Hyper-V Hypervisor Virtual Processor(*)\%Total Run Time" metric shows about 60-70%.

Is it possible to obtain "real" CPU utilization for Guest system? How to make "Hyper-V Hypervisor Virtual Processor(*)\%Total Run Time" 100%?

I have prepared the non-administrator user for collecting data using WMI.

I can query any namespace using this user except root/MSCluster. For root/MSCluster it returns 'access denied'. At the same time, I can successfully query it using domain administrator account.

Get-WSManInstance wmi/root/mscluster/* -Enumerate -Filter "SELECT * FROM MSCluster_Resource" -ComputerName host1.corp.com -Authentication Kerberos -Credential [email protected]

'[email protected]' is added to 'Performance Monitor Users', 'Distributed COM Users' and 'WinRMRemoteWMIUsers__' groups, 'Event Log Read Permission' is granted, full access is granted for all WMI namespaces, full DCOM access is granted

I need to allow access to my site without SSL certificates from my office network and with SSL certificates outside.

Here is my configuration:

 <Directory /srv/www>
  AllowOverride All

  Order deny,allow
  Deny from all
  # office network static IP
  Allow from xxx.xxx.xxx.xxx

  SSLVerifyClient require
  SSLOptions +FakeBasicAuth
  AuthName "My secure area"
  AuthType Basic
  AuthUserFile /etc/httpd/ssl/index
  Require valid-user
  Satisfy Any

 </Directory>

When I'm inside network and have certificate - I can access. When I'm inside network and haven't certificate - I can't access, it requires certificate.

When I'm outside network and have certificate - I can't access, it shows me basic login screen When I'm outside network and haven't certificate - I can't access, it shows me basic login screen

and following configuration works perfectly

 <Directory /srv/www>
  AllowOverride All

  Order deny,allow
  Deny from all
  Allow from xxx.xxx.xxx.xxx

  AuthUserFile /srv/www/htpasswd
  AuthName "Restricted Access"
  AuthType Basic
  Require valid-user
  Satisfy Any

 </Directory>

I have one FTP account for customers and I want they upload files, but they should not see what already uploaded by other customers.

Is that possible?

If I will disaalow directory listing that will "break" frp connection.

Munin graphs is very small. That makes some multigrpahs useless for me. Is it possible to increase graph image size?

I have a git (gitosis) repo where every developer have a main branch. I have a script in post-update hook that rebuild main web site and test websites for every developer on every PUSH.

I want to rebuild only site corresponding to the committed branch, but don't know how to determine committed branch name. Could anyone help?