GlusterFS mounts fail at boot on CentOS

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 […]

Genome assembly likes RAM!

This is what it looks like when you do a genome assembly and run out of memory… The machine in question actually has 384GB of RAM (not much, as far as machines which do genome assembly go!). Assembling a genome is like doing a massive puzzle; you need to have all the “pieces” in contiguous […]

Force PHPMyAdmin to use HTTPS

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/, add this to the bottom: $cfg['ForceSSL'] = true; I like mod_rewrite and […]

“Welcome to Uganda Telecom”

Something a little close to home from Jacob Appelbaum‘s talk at the Chaos Computer Congress in Hamburg yesterday. During a section about GSM spoofing equipment used by the NSA, he mentions one epic fail by the UK GCHQ. Apparently they set up fake GSM equipment at the Ecuadorian embassy in London (where Julian Assange has […]

“No data available” error in GlusterFS brick log

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/ 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 […]