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@martinkennelly
martinkennelly / gist:dbf8a2eb043bdde06bebdbd3e00a449a
Created August 8, 2023 09:30
Getting ovn-nbctl: unix:/var/run/ovn/ovnnb_db.sock: database connection failed () ?
You can possibly resolve it in two ways:
1. If OVN is in HA, exec onto the pod who is the current leader and execute `ovn-nbctl --no-leader-only show`
2. Find all the instances IPs and execute `ovn-nbctl --no-leader-only --db=...`

2. System Performance: Methodologies

2.1 Terminology

  • IOPS: Input/output operations per second is a measure of the rate of data transfer operations. For disk I/O, IOPS refers to reads and writes per second.
  • Throughput: The rate of work performed. Especially in communications, the term is used to refer to the data rate (bytes per second or bits per second). In some contexts (e.g., databases) throughput can refer to the operation rate (operations per second or transactions per second).
  • Response time: The time for an operation to complete. This includes any time spent waiting and time spent being serviced (service time), including the time to transfer the result.
  • latency: A measure of time an operation waiting to be serviced. In some contexts, it can refers to the entire time for an operation, equivalent to response time.
  • Utilization: với các resource cung cấp theo kiểu request, đây là cách đo lường cho mức độ resource đc sử dụng (how busy a resource is), dựa trên thời gian sử
@brasey
brasey / Configure systemd-resolved to use a specific DNS nameserver for a given domain.md
Created October 25, 2019 14:38
Configure systemd-resolved to use a specific DNS nameserver for a given domain

Configure systemd-resolved to use a specific DNS nameserver for a given domain

Use case

Given

  • I use a VPN to connect to my work network
  • I'm on a Linux computer that uses systemd-resolved
  • I have a work domain called example.com
  • example.com is hosted by both public and private DNS nameservers
@mohanpedala
mohanpedala / bash_strict_mode.md
Last active September 18, 2025 03:11
set -e, -u, -o, -x pipefail explanation