[ceph-users] Re: *****SPAM***** Re: librbd 4k read/write?

To allow for faster linear reads and writes, please create a file, /etc/udev/rules.d/80-rbd.rules, with the following contents (assuming that the VM sees the RBD as /dev/sda):

KERNEL=="sda", ENV{DEVTYPE}=="disk", ACTION=="add|change", ATTR{bdi/read_ahead_kb}="32768"

Or test it without any udev rule like this:

bloskdev --setra 65536 /dev/sda

The difference in numbers is because one is in kilobytes and one is in 512-byte sectors.

Mandatory warning: this setting can hurt other workloads.

Such as what workloads? Would the results show in the average latency rbd overview? Or is it better to monitor somewhere else?