RBD latency with QD=1 bs=4k

You might be asking yourself, why talk about QD=1 bs=4k? Well, from the experience of Wido den Hollander, our colleague at 42on, a single thread IO latency is very important for many applications. What we see with benchmarks is that people focus on high amounts of bandwidth and large amounts of IOps. They simply go […]

Using TRIM/DISCARD with Ceph RBD and libvirt

TRIM/DISCARD Using TRIM/DISCARD you can give back free space to a Ceph cluster. Normally, any thin provisioned block device will keep on growing until its maximum size while being used. Using the DISCARD command a underlying block device can be instructed to discard blocks which do not contain data. In the case of Ceph’s RBD […]