Technology

Technology

Capacitor

Signal filtering [202] Capacitors are divided into polarized and non-polarized depending on whether the direction of their inclusion in the circuit is important. Generally speaking, capacitors filter the waveform of the power source. It is assumed that the longer lead from the capacitor is the positive pole, which is sometimes reflected in the marking in the diagram. Electrolytic capacitors consist of a metal cover and an electrolyte lined with paper. Non-polar (non-polarized) capacitors can be made of ceramic elements or foil. There are also tantalum capacitors which both offer high capacitance and relatively low losses. The physical size of a

Technology

growfs fsck required (pfSense)

In case you’ve managed to overcome other issues with system unable to boot, disk size not updated then there might be still one problem left. Sometimes resizing with gpart works fine but file system resize does not. I’ve encountered such issue and frankly speaking I’m not quite sure what is root cause of it. Is says that file system is dirty and I should run fsck which can be executed from console selecting number 5 and then F letter. System reboots and makes file system check. It says that the file system is fine, so it’s quite confusing. Solution for

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Azure FreeBSD (pfSense) not able to pick boot partition after disk resize

Following previous struggles on pfSense FreeBSD on Azure. After resizing disk Microsoft starts at some point adding an another drive which is temporary one. I do not need this by any means. It seems that NetGate pfSense template is also not quite compatible with cloud-init as the platform tries to execute systemctl which is not present here. The problem with this is that FreeBSD will not be able to pick which partition it should start from. Fix for this is pretty simple. Just go and edit /etc/fstab and instead of pointing to some virtual labels. In my case it was

Technology

Resize drive and partition on FreeBSD 12 (pfSense)

Recently I described how to increase drive, partition and filesystem on FreeBSD in Azure virtual machine. It turned out that this scenario was little bit different from a virtual machine running on top of VMware. First of all, with or without vm-tools I was not able to get updated drive size: It gives messages that rescanning was successful, but actually it did not apply new values. However we can check new drive size with the following command: If on your system you get same results, then you need to reboot. There is also a difference of having swap space. First

Technology

WordPress migration

After 2 years on DigitalOcean I’ve decided to move out. Not because it’s bad or expensive, but because I need one more feature which is IDS/IPS. By default WordPress installation on DO contains fail2ban, which is fine, but I find Suricata way more powerful. To start with, I’ve created a backup using All-In-One WP migration and Increate Max File Size. Former is responsible for dumping all of the site content, and the latter is giving a ability to upload this dump file into new WordPress installation. But… you also need to edit one file in your need WP setup: With

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Proxmox setting locale failed

If you log in to Proxmox’s shell and see error stating that “setting locale failed“, then execute the following command to get rid of that message: Not quite sure why it happens, but I see it almost all the time.

Technology

Recover pfSense from out of disk space and config.xml corruption

I use NetGate pfSense+ version 22 based on FreeBSD 21. I encountered a problem of running out of disk space because of packet logging enable in Suricata. Out of a sudden there was high traffic and therefore high logs production. Disk space utilization was over 100%. Now there is a problem with /config/config.xml file, there is no VPN, Suricata, pf configuration available from the UI. Dashboard is corrupted also. However there is /config/backup folder with backed up configuration files. I’ve taken the last known good with proper file size and put it in place. After reboot it works just fine.

Technology

Ruby on Rails vs PostgreSQL 14 partitioning primary keys

Starting from PostgreSQL 10 we have available new type of paritioning, which is declarative one. Before we had inheritance which is also good but has some limitations. Now, with declarative partitioning user need not to specify partition name while inserting data. To create partitioned table: There are few things worth explaining. First one is BIGSERIAL data type. It is a bigger form of integer type with automatic sequence creation, which is very convenient. Second thing is PARTITION BY RANGE(columnname). It defined that the data will be spread across paritions based on created_at date range. It positively affects query performance. To

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Allow .local domain suffix to be resolved

On many chances you may need to configure some domains using .local suffix. Unfortunately this is covered by RFC 6762 (multicast DNS). On specific Linux distributions you will not be able to resolv such domains using DNS server you set either in the machine or in the cloud settings (for instance Azure). How to you know that the DNS query is not reaching your desired DNS server? In case you use named, then first enable query logging by the following comman: Now DNS queries from the clients who set that particular DNS server as its resolved will be visible in