A most unusual temporal issue

By | Technical | No Comments

Most of us have suffered time-related woes, dealing with servers that just can’t keep their clock straight even with NTP. Well we’ve just come across a new one, and NTP isn’t going to save the day – what happens when you have multiple misbehaving clocks? We first noticed the problem when reloading the firewall on […]

Read More

Pulling apart Ceph’s CRUSH algorithm

By | Technical | One Comment

As you’ve probably noticed, we’ve been evaluating Ceph in recent months for our petabyte-scale distributed storage needs. It’s a pretty great solution and works well, but it’s not the easiest thing to setup and administer properly. One of the bits we’ve been grappling with recently is Ceph’s CRUSH map. In certain circumstances, which aren’t entirely […]

Read More

Bughunting in Ceph’s radosgw: ETags

By | Technical | No Comments

RADOS Gateway (henceforth referred to as radosgw) is an add-on component for Ceph, large-scale clustered storage now mainlined in the Linux kernel. radosgw provides an S3-compatible interface for object storage, which we’re evaluating for a future product offering. We’ve spent the last few days digging through radosgw source trying to nail a some pesky bugs. […]

Read More

Inquisitio interrupta

By | Technical | 2 Comments

A customer’s Django app has been giving us hell for a little while now, something we’ve recently tracked down to dodgy signal-handling in some MySQL library code. Despite only showing up a dozen times in every 600 million queries or so, we’ve nailed it! It turns out the bug has been hanging around, on and […]

Read More