[ceph-users] Re: mclock and massive reads

Hi Luis,

So our question, is mClock taking into account the reads as well as the writes? Or are the reads calculate to be less expensive than the writes?

mClock treats both reads and writes equally. When you say "massive reads", do you mean a predominantly read workload? Also, the size of the reads is also factored in to arrive at the cost of the operation. In general, the cost of an I/O operation in mClock is proportional to its size. The higher the cost, the longer the operation stays in the queue. That being said, the implementation of mClock on pacific is experimental at best. I would recommend upgrading to either quincy or reef considering the significant improvements that were made both in terms of scheduling and usability. -Sridhar