Sysadmin

I had a trouble with a long process running and wish to know how much I/O this process is doing, so I wrote this quick and dirty python 2.x script: import time,sys,datetime def read_stat(pid): f=open("/proc/%s/io" % pid ,"r") for line in f: if line.startswith('rchar'): rchar=line.split(':')[1] continue if line.startswith('wchar'): wchar=line.split(':')[1] continue f.close() return int(rchar),int(wchar) pid=sys.argv[1] r0,w0 = read_stat(pid) while 1: time.sleep(1) r1,w1 = read_stat(pid) print "%s\t\tr=%s\t\tw=%s" % (datetime.datetime.now().time(),r1-r0,w1-w0) r0,w0=r1,w1 You must give the process PID number as input to the script. In the output you get the read/write throughput of the process in bytes per second, for instance: ...

It’s always recommended to backup your data for safety, but for safety AND security let’s encrypt your backups! to compress and encrypt with ‘mypassword’: tar -Jcf - directory | openssl aes-256-cbc -salt -k mypassword -out backup.tar.xz.aes to decrypt and decompress: openssl aes-256-cbc -d -salt -k mypassword -in backup.tar.xz.aes | tar -xJ -f - Another trick with the tar command is useful for remote backups: tar -zcvfp - /wwwdata | ssh root@remote.server.com "cat > /backup/wwwdata.tar.gz"

This script is useful to delete old messages in “Junk” mail folders (Spam, Trash) automatically after some days. adapted from these notes to work on debian/postfixadmin/dovecot #!/bin/bash # # itera sulle mailbox cancellando messaggi vecchi # per default, nel cestino 30gg e Spam 15 gg # # MySQL details HOST="127.0.0.1"; USER="put_here_your_mysql_user"; PWD="put_here_your_mysql_password"; MYSQL="/usr/bin/mysql"; # dovecot details DOVEADM="/usr/bin/doveadm"; TEMPFILE=$(/bin/mktemp) # Output sql to a file that we want to run echo "use postfixadmin; select username from mailbox" > $TEMPFILE # Run the query and get the results (adjust the path to mysql) results=$($MYSQL -h $HOST -u $USER -p$PWD -N < $TEMPFILE); # Loop through each row for row in $results do echo "Purging $row Trash and Junk mailbox..." # Purge expired Trash $DOVEADM -v expunge mailbox Trash -u $row savedbefore 30d # Purge expired Spam $DOVEADM -v expunge mailbox Spam -u $row savedbefore 15d done rm $TEMPFILE