braindevices

reflink in mounted volume

podman run -v /data/devspace/dummy/test/A:/mnt/A:Z -v /data/devspace/dummy/test/B:/mnt/B:Z --rm -it ubuntu:latest /bin/bash

following works fine

root@68ec02c9b450:/mnt# cp --reflink=always A/test10M.bin A/reflinked.bin
[dummy@host test]$ xfs_io -r -c 'fiemap' A/reflinked.bin 

braindevices

XFS reflinks vs BTRFS snapshots

reflinks in XFS

reflinks can be used as CoW mechanism for XFS since 4.17.0-2.el8

This feature enables two or more files to share a common set of data blocks. When either of the files sharing common blocks changes, XFS breaks the link to common blocks and creates a new file.

so with cp --reflink we can create CoW blocks already. This is similar to btrfs CoW. We can simply do following to mimic the snapshot:

find /root -mindepth 1 -maxdepth 1 -not -name "backup" -exec cp -r --reflink {} /root/backup/$(date)/ ;

braindevices

# each bottleneck blcok has 4 conv that k>1
btn = [(3,1)]*4
# stem, C1 (1), C2 (2), conv, C3 (4), conv, C4 (6), conv, C2f, C5 (SPPF) (9)
idx_Cs = [1,2,4,6,9]
blocks = [
  [(3,2)], # conv
  [(3,2)], # conv
  btn*1, # C2f n=3*d
  [(3,2)], # conv
  btn*2, # C2f n=6*d

braindevices

#!/bin/bash
set -x
systemctl -T -o verbose daemon-reload
systemctl -T -o verbose disable --now test-timer.timer
set -e
wait_secs=20
run_at_time=$(date -d "+${wait_secs}sec" +"%H:%M:%S")
logfile=/tmp/test-timer-output
if [ -f ${logfile} ]
then

braindevices

docker just do not get along with libvirt, iptables, nptables, firewalld, etc

why my container isolation comes and gos? iptables, nptables, firewalld, who did what?!

there is almost NOT legacy iptables command (iptables) on modern OS (RHEL8, ubuntu22, etc) there can still be some lagecy ip_tables module loaded:

lsb_release -d; lsmod | grep tables; iptables -V
Description:    Fedora release 38 (Thirty Eight)
nf_tables             368640  1454 nft_compat,nft_chain_nat
nfnetlink              20480  8 nft_compat,nfnetlink_acct,nf_conntrack_netlink,nf_tables,ip_set
Description:    Red Hat Enterprise Linux release 8.8 (Ootpa)

braindevices

The styler gives us a easy way to format the dataframe and maintain the format across different kind of output: html, excel, etc.

However, one of my friends has spot a problem of it, the styler.to_excel() output some how supressed some advanced formating of XlsxWriter. Here is an example:

import pandas as pd
data = pd.DataFrame({"A":list(range(10,12)), "B":["abcdefgafafadf", "afbafafafafadfadfadf"]})
with pd.ExcelWriter("/tmp/test.xlsx") as writer:
    data.style.apply(lambda x: ['background-color: red']*2 if x['A']==11 else [None]*2, axis=1).to_excel(writer, index=False)
 writer.sheets["Sheet1"].write(3, 1, "Some long text to wrap in a cell")

braindevices

#btrfs benchmark for daily used desktop OS

braindevices

1–10	11–20	20–30
6940	5839	6007
6615	6957	6314
6169	6877	6224
6142	6324	6210
6492	6685	6961
6908	5964	6475

braindevices

#!/usr/bin/env python  
#coding=utf-8
#  
# Generate a list of dnsmasq rules with ipset for gfwlist
#  
# Copyright (C) 2014 http://www.shuyz.com   
# Ref https://code.google.com/p/autoproxy-gfwlist/wiki/Rules    
 
import urllib2 
import re

braindevices

# coding: utf-8
import tushare as ts
import pandas as pd
import pickle


stock_list = ts.get_stock_basics()


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