kofemann

#
# Based on info providef at http://fasterdata.es.net/
#

# allow testing with buffers up to 64MB
net.core.rmem_max = 67108864
net.core.wmem_max = 67108864

# Enable memory auto tuning
net.ipv4.tcp_moderate_rcvbuf = 1

kofemann

#
# tuned configuration for PostgresSQL servers
# /usr/lib/tuned/postgres-db-server/tuned.conf
#

[cpu]
force_latency=1
governor=performance
energy_perf_bias=performance
min_perf_pct=100

kofemann

#!/usr/bin/env python3

# Licensed under GNU GENERAL PUBLIC LICENSE Version 2

#
# parses files produced by : `tshark -r file.pcap -q -n -T pdml`
#

import xml.sax
import sys

kofemann

Token-based storage access problem statement

by Tigran Mkrtchyan, Deutsches Elektronen-Synchrotron DESY, June 2023.

Status of this Memo

By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668.

kofemann

DATA AND METADATA COHERENCE
       Some modern cluster file systems provide perfect cache coherence among their clients.  Perfect cache coherence among disparate NFS clients is expensive to achieve, especially on wide area networks.  As such, NFS settles for weaker cache coherence that satisfies the requirements of most file sharing types.

   Close-to-open cache consistency
       Typically file sharing is completely sequential.  First client A opens a file, writes something to it, then closes it.  Then client B opens the same file, and reads the changes.

       When an application opens a file stored on an NFS version 3 server, the NFS client checks that the file exists on the server and is permitted to the opener by sending a GETATTR or ACCESS request.  The NFS client sends these requests regardless of the freshness of the file's cached attributes.

       When the application closes the file, the NFS client writes back any pending changes to the file so that the next opener can view the changes.  This al

kofemann

Guava -> Java 8 cheat sheet

This is a one way mapping. If you used to use Guava futures, you probably want to do the java 8 equivalent. This does not mean that the reverse mapping works.

Guava style	Java 8 style
Listenablefuture.addListener(callback)	future.whenComplete(callback)
Futures.addCallback(callback)	[future.whenComplete(callback)](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletionStage.html#whenComplete-java.ut

kofemann

#!/usr/bin/env python3

# This program runs "make --dry-run" then processes the output to create a visual studio code
# c_cpp_properties.json file

# Origin:
#   https://iotexpert.com/2020/06/01/stupid-python-tricks-vscode-c_cpp_properties-json-for-linux-kernel-development/
#   by: Alan Hawse
 
import json

kofemann

#
# postgres cluster in kubernetes with max 8 replicas
#
# the master is always on ${host}-0
#


#
# postgres master/slave configuration
#

kofemann

package dev.kofemann.playground;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.epoll.EpollEventLoopGroup;

kofemann

package org.dcache.chimera.posix;


import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.UUID.randomUUID;

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import java.io.FileReader;
import java.io.IOException;