Knowledge Base for IT Professionals, Teachers and Astronauts
Every time I start a PowerShell terminal on my Windows VMware Fusion virtual machine I have to map the host drive of my MacBook Pro. I execute this command in PowerShell:
New-PSDrive -Name z -Root "\\vmware-host\Shared Folders" -PSProvider FileSystem -Scope Global -Persist:$trueWhen a file is saved with BOM (byte-order mark) on a Mac or Linux machine Windows PowerShell cannot execute the script.
Unfortunately the “cat” command does not show the byte-order mark at the beginning of the file. Some editors show a question mark at the beginning of the file.
I have discovered it when I issued the “git diff” command:
<U+FEFF>
To remove the BOM in Visual Studio Code
The “git diff” command shows the removal of the BOM
Some sites do not load properly when old cached data is stored in the web browser.
To clear the cached images, cookies and other site related data for one specific site in Chrome
We didn’t use the developer tools, but to be able to see the options on the refresh icon we need the tools open.
To find queries that block others in Microsoft SQL databases, execute
select session_id,command,wait_type,blocking_session_id from sys.dm_exec_requests;This returns the list of active sessions and indicates what session blocked it.
To get the query of a session, execute
dbcc inputbuffer(THE_SESSION_ID)When a database is migrated to another server by copying the database file or restoring it from a backup file, the original database user account references are also carried with it.
Those accounts contain the account IDs specific to the original database server.
To provide access to the restored database on the new database server we need to delete the old user accounts from the restored database and configure the database access in the new database server. This will re-create the user accounts with the correct IDs in the restored database.
For more information see https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/troubleshoot-orphaned-users-sql-server?view=sql-server-ver15
When the Chef aws cookbook’s ebs_volume.rb resource tries to bring a volume online, partition, and format it we get the error message:
RuntimeError: Volume vol-… attached at xvdf but does not conform to this resource’s specifications
C:/chef/cache/cookbooks/aws/resources/ebs_volume.rb:46:in `block in class_from_file’
Make sure the “size” attribute value in the aws_ebs_volume resource call matches the actual size of the volume in GiB.
When we tried to install the Microsoft Access Database Engine and Office 2007 System Driver on a Windows Server 2016 an error message popped up immediately:
The installation of this package failed
When we ran the installation with the logging option, we have found a message at the bottom of the file:
./AccessDatabaseEngine_x64_2010 /passive /log:enginelog.txtWill create the folder ‘\MSECache\AceRedist\1033’
CActionCreateFolder::execute ends
CActionIf::execute starts
Begin evaluation of the condition
The property ‘SYS.ERROR.INERROR’ is equal to ‘1’
The installer could create the \MSECache\AceRedist\1033 on the D: drive where we executed the program, but for some reason the directory was empty.
We decided to approach the problem in two steps:
./AccessDatabaseEngine_x64_2010 /passive /extract:extract_dir_2010
./AccessDatabaseEngine-2007-Office-System-Driver /passive /extract:extract_dir_2007
cd extract_dir_2010
./AceRedist.msi /passive
cd ../extract_dir_2007
./AceRedist.msi /passiveOlder PowerShell versions do not use TLS1.2 as the default version during the SSL handshake. When the API requires TLS1.2 the error message appears:
Invoke-WebRequest : The request was aborted: Could not create SSL/TLS secure channel.
To force PowerShell to use TLS1.2 during the SSL handshake, issue this command before executing the Invoke-Webrequest
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;
Invoke-WebRequest ....
When the Linux disk drive is full, first we need to identify the reason for the drive overuse. Many times the drive is filled with one large log file, that can be identified and truncated.
To list the directory sizes under the current directory execute
du -sh *To empty a file, overwrite it with nothing, so the process that writes into it still can access it.
cat /dev/null > ./MY_LARGE_LOG_FILEWhen we free up the disk space, the server needs time to recover and do some housekeeping. The load average numbers show how busy the server was in the recent minutes. Check the load on the computer with
uptime23:58:50 up 318 days, 16:32, 1 user, load average: 0.03, 5.34, 18.68
The load averages are from the past 1, 5, and 15 minutes
If extra drive space is needed, enlarge the volume. We also need to grow the partition, so the operating system can access the additional space on the volume.
Grow the partition to use the entire volume. Use the growpart command, and specify the name of the volume and the partition number.
sudo growpart /dev/nvme0n1 1If the file system is xfs, update the xfs file system metadata to use the entire partition
sudo xfs_growfs /To be able to fully control the routing of a DNS name use Route 53
In the Route 53 console click the Create Hosted Zone button
Create a new public Hosted Zone
Return to the domain registrars website and set the name servers to use the AWS Route 53 hosted zone’s name servers
If HTTP is sufficient, you can route directly to the S3 bucket
For HTTPS connections create a CloudFront distribution for the S3 bucket, attach an SSL certificate to it and route to the CloudFront Distribution
To route to an ECS cluster, select the Application load balancer
