I use Monit to do lightweight monitoring and alerting for my services. Nothing advanced, just one host running monit which probes other servers via TCP, UDP, ICMP, etc to see if services are accessible. Monit can do much more if you install it on each machine itself, but I’m not interested in that right now […]
After nearly a year of running GlusterFS on my compute cluster, I’m surprised it took me so long to run into this bug. I rebooted one of my compute nodes and found that the machine hung at Mounting network filesystems during the boot sequence. From the volume log — /var/log/glusterfs/<volname>.log — on the client, it […]
You want to use PHPMyAdmin. You want to force HTTPS so you don’t send plain-text MySQL credentials over the wire/air. You start fiddling with mod_rewrite and troubleshooting your Apache’s myriad of virtual hosts and included config files. There’s a better way! In /etc/phpMyAdmin/config.inc.php, add this to the bottom: $cfg[‘ForceSSL’] = true; I like mod_rewrite and […]
Recently I was poring over my GlusterFS brick logs trying to troubleshoot a problem with self healing and I saw some (6,000+!) errors which alarmed me: [2013-11-22 09:21:51.138732] E [posix.c:2668:posix_getxattr] 0-homes-posix: getxattr failed on /mnt/gfs/wingu0/sda1/homes/yajamma/qdd_programs/qdd_files/qdd3_beta/MS_extract.pl: system.posix_acl_access (No data available) It turns out this error isn’t an error after all, and there’s a patch merged upstream […]
Ever since the Sandy Bridge microarchitecture, Intel CPUs have been coming with hardware-accelerated AES support (aka “AES-NI”, new instructions). I figured it would be interesting see a comparison between AES with and without the hardware acceleration on my Intel Core i5-3317U CPU (Ivy Bridge) on Arch Linux. According to a post on the OpenSSL Users […]