Disk performance baseline

The disk performance baseline test will be done in two steps. First, we will measure the performance of a single disk, and after that, we will measure the performance of all the disks connected to one Ceph OSD node simultaneously.

Note

To get realistic results, I am running the benchmarking tests described in this recipe against a Ceph cluster deployed on physical hardware. We can also run these tests on the Ceph cluster, hosted on a virtual machine, but we might not get appealing results.

Single disk write performance

To get the disk read and write performance, we will use the dd command with oflag set to direct in order to bypass disk cache for realistic results.

How to do it...

Let's benchmark single disk write performance:

1. Drop caches:

        # echo 3 > /proc/sys/vm/drop_caches

2. Use dd to write a file named deleteme of the size 10G, filled with zeros /dev/zero as the input file to the directory where Ceph OSD is mounted, that is, /var/lib/ceph/osd/ceph-0/:

       ...