free -m | grep Mem | awk '{print $3}'
Use that and feed memory usage into a graphite server every minute from a cron script:
*/1 * * * * echo "some.system.memoryusage `free -m | grep Mem | awk '{print $3}'` `date +%s`" | nc graphite.somedomain.com 2003
Sometimes you just need to get rid of all that trackback data from your WordPress database. Here’s how to do it manually from your MySQL command line:
DELETE FROM wp_comments WHERE comment_type='trackback'; DELETE FROM wp_comments WHERE comment_type='pingback';
Great, but now your comments counts are all out of whack, since that integer is stored in the wp_posts table. Here’s how to check that:
SELECT wpp.id, wpp.post_title, wpp.comment_count, wpc.cnt
FROM wp_posts wpp
LEFT JOIN (
SELECT comment_post_id AS c_post_id, count(*) AS cnt FROM wp_comments
WHERE comment_approved = 1 GROUP BY comment_post_id) wpc
ON wpp.id=wpc.c_post_id
WHERE wpp.post_type IN ('post', 'page')
AND (wpp.comment_count!=wpc.cnt OR (wpp.comment_count != 0 AND wpc.cnt IS NULL)
);
And here’s how to fix it (make a backup of your database first, just in case):
UPDATE wp_posts wpp
LEFT JOIN (
SELECT comment_post_id AS c_post_id, count(*) AS cnt FROM wp_comments
WHERE comment_approved = 1 GROUP BY comment_post_id) wpc
ON wpp.id=wpc.c_post_id
SET wpp.comment_count=wpc.cnt
WHERE wpp.post_type IN ('post', 'page')
AND (wpp.comment_count!=wpc.cnt OR (wpp.comment_count != 0 AND wpc.cnt IS NULL)
);
Cheers!
Go ahead and install the samba packages:
sudo yum install samba samba-client samba-common smbd --version sudo chkconfig smb on sudo chkconfig nmb on sudo nano /etc/selinux/config
Disable SELINUX by editing /etc/selinux/config and make one small change:
SELINUX=disabled
Make some additions to iptables:
sudo iptables -I INPUT 4 -m state --state NEW -m udp -p udp --dport 137 -j ACCEPT sudo iptables -I INPUT 5 -m state --state NEW -m udp -p udp --dport 138 -j ACCEPT sudo iptables -I INPUT 6 -m state --state NEW -m tcp -p tcp --dport 139 -j ACCEPT sudo service iptables save
NOW, restart the server:
sudo reboot now
Backup and modify smb.conf:
sudo cp /etc/samba/smb.conf /etc/samba/smb.conf.bak sudo rm /etc/samba/smb.conf sudo touch /etc/samba/smb.conf sudo nano /etc/samba/smb.conf
The file should contain:
[global] workgroup = WORKGROUP server string = server_name security = user map to guest = bad user [private-share] path = /media/sdd valid users = @smbgrp guest ok = no writable = yes browsable = yes
Restart smb and nmb:
sudo service smb restart sudo service nmb restart
Add your groups and add users to them:
sudo groupadd smbgrp cd /media/sdb sudo mkdir secureshare sudo chown -R username:smbgrp secureshare/ ls -l sudo chmod -R 0770 secureshare/ sudo usermod -a -G smbgrp username sudo smbpasswd -a username sudo service smb restart sudo service nmb restart sudo testparm
Now connect from a windows PC using credentials from CentOS server by right-clicking within “Computer” and selecting “Add a network location”. Follow the prompts and your share will be usable from Windows!
If you cannot connect, it’s most likely the firewall on the CentOS machine. Backup and then flush iptables to test if needed, and then rebuild your firewall accordingly. If you cannot get access to your shares, you have a permissions problem on the server end. Check users, groups, share permissions, and smb.conf for proper values.
You’re welcome 😉
for file in *.jpg; do convert $file -resize 1024x1024> $file; done
find . -type f -exec convert {} -resize 700×700> {} ;
All of this assumes LAMP (specifically CentOS 6, MySQL server 5.5, Apache 2+ with mod-status enabled)
On mysql server:
watch -n 1 "mysql -e 'show processlist';"
Look for sleeping connections that are staying open for a while. Watch for a trend. When you see a connection that you think will stay open for long enough, note it’s port number. Open second shell. Do the following:
netstat -lnap | grep 12345
– where the 12345 is the port number from the mysql process list. If/when you get a result, note the number to the right, next to “ESTABLISHED”. Next – open a web browser. Navigate to http://yourserver.com/server-status and do a search for that number (that’s the PID (process id). The highlighted line is now the process that caused the long-running MySQL thread.
Repeat this process a bunch of times until you have a good overview of what’s causing problems. Viola! Debug success, and it’s time for beers!
( This week, we’re drinking Sam Adams Boston Lager for our friends in Boston )
find . -name “*.mp3” -exec rename .mp3 .mp3srbad {} ;
watch -n 1 “mysql -h 10.0.0.1 -u username -pPASSWORD -e ‘SHOW PROCESSLIST;’”
watch -n 1 “free -ml”