Below are examples of importing and exporting MySQL databases from a Linux terminal.
Export the database to a file like this:
Continue reading “Import and export MySQL databases”Vyacheslav Gapon – personal blog, manuals, articles, notes, development
Below are examples of importing and exporting MySQL databases from a Linux terminal.
Export the database to a file like this:
Continue reading “Import and export MySQL databases”system-config-samba – a simple application for configuring samba with a graphical interface.
Installing by the command:
sudo apt-get install system-config-samba
Running:
sudo system-config-samba
Allows you to add shared folders, samba users, assign permissions to folders, etc., all changes are saved to samba configuration files.
There were somehow many invalid phone numbers and email addresses in Privat24, I wanted to delete them, the tick “Actual” was naturally removed.
After communicating with technical support, I was informed that you can delete the email yourself by sending an SMS with the text OFF + mail@example.com to number 10060, where mail@example.com is the address of the current mail (when abroad, SMS should be sent to +380920003700).
And the operator of technical support made an application for removing phone numbers on their own and after a while they disappeared from the settings of the account.
By default, Bind9 logs are written to the system log / var / log / syslog and to separate them, I will perform the actions that I will point out below.
Continue reading “Configuring Bind9 logs”BIND (Berkeley Internet Name Domain) — open and the most common implementation of the DNS server, which ensures that the DNS name is converted to an IP address and vice versa.
Continue reading “Installing and Configuring DNS Server BIND9”You can configure the reverse DNS record (PTR) for the Hetzner server in the control panel robot.your-server.de
Continue reading “Configuring Reverse DNS (PTR) in Hetzner”It was necessary to somehow configure the Reverse DNS zone for the mail server, since some servers did not want to receive mail from it.
Let’s assume our domain mail.example.com located on the IP address 192.168.1.100, and 192.168.1.1 – the server of the Internet provider.
You can check from Windows with commands (where 192.168.1.100 for example is the address of our mail server, and 192.168.1.1 DNS on which the request is sent):
nslookup mail.example.com nslookup 192.168.1.100 nslookup 192.168.1.100 192.168.1.1
In response, the first command will be 192.168.1.100, and in response the second one is nothing (it should be mail.example.com), since the PTR record is not configured in DNS.
From Linux, you can check:
dig -x 192.168.1.100
At the registrar of domain names in DNS we will add the NS-server of the Internet provider ns1.example.com 192.168.1.1.
On the provider’s server (on the test I use Bind9 on Ubuntu Server), open the DNS configuration file for example in the nano editor (CTRL+X for exit, y/x and Enter for saving or canceling changes):
sudo nano /etc/bind/named.conf
And add the following lines:
zone "1.168.192.in-addr.arpa" { type master; file "/etc/bind/1.168.192.in-addr.arpa"; };
The first line indicates which zone we will manage, the second type – the main one (this DNS will manage it), the third one – in which file the configuration for this zone will be registered.
Open a new file for zone settings:
sudo nano /etc/bind/1.168.192.in-addr.arpa
And add to it:
$TTL 3600 @ IN SOA ns1.example.com. admin.example.com. ( 2016112301 ; Serial 21600 ; refresh 3600 ; retry 3600000 ; expire 86400 ) ; minimum IN NS ns1.hosting.com. IN NS ns2.hosting.com. $ORIGIN 1.168.192.in-addr.arpa. 100 IN PTR mail.example.com.
admin.example.com – the contact address of the person responsible for the zone, the @ symbol is not indicated.
Serial – this is the serial number of the zone file version, it should change to the big side with each change, it is usually written in the form of the year month the number is the number of the change, according to it other DNS determine that it is necessary to update the information.
Refresh – the time interval in seconds through which the secondary server will check whether the information needs to be updated.
Retry – the time interval in seconds through which the secondary server will retry calls on failure.
Expire – the time interval in seconds through which the secondary server will consider the information it has obsolete.
Minimum – the interval of information lifetime on caching servers.
ns1.hosting.com and ns2.hosting.com this is the DNS of this domain.
The number 100 in the last line means the end of IP address 192.168.1, similarly you can specify entries for other domains, for example 101 IN PTR … for 192.168.1.101, etc.
Restart the DNS server to apply the changes.
Bind9 can be commanded by:
sudo /etc/init.d/bind9 restart
Done.
See also:
Configuring Reverse DNS (PTR) in Hetzner
fio (flexible I/O tester) – a tool that creates write / read streams to evaluate the performance of the file system, so to speak, see the speed in MB / s, IOPS, etc.
Continue reading “Test iops using fio”In Huawei OLT, there are several types of VLAN, briefly describe them:
Continue reading “Description of VLAN Types in Huawei OLT”ioping – a simple tool for monitoring disk I/O delays in real time, similar to ping showing network latency.
You can install in Ubuntu / Debian using the command:
sudo apt-get install ioping
Here is an example of a run with 10 requests for a delay test to the / tmp directory:
ioping -c 10 /tmp
An example of a query with an interval of 0.2ms and an increased query size:
ioping -i 0.2 -c 10 -s 1M -S 5M /tmp
Test to disk:
ioping -R /dev/sda ioping -RL /dev/sda
I’ll describe the possible startup options:
-c count (stop after the specified number of requests)
-w deadline (stop after the specified amount of time)
-p period (display raw statistics after each specified number of requests)
-P period (display raw statistics after each specified number of seconds)
-i interval (the interval between requests in seconds)
-s size (request size (4k))
-S size (size of the working set)
-k (after the command is finished, leave (do not delete) the working file ioping.tmp)
-L (sequential operations instead of random ones, this will also set the query size to 256k (like -s 256k))
-A (asynchronous I/O)
-C (cached I/O)
-D (straight I/O)
-B (do not display execution information, it will only appear when the command is finished in raw format)
-q (do not display execution information, it will be displayed only when the command completes)
-h (display help)
-v (view version)