cool ! That helped a lot ! Is there any more source or sources that can
explain Straw2 bucket more in detail. Or lets say mapper.c code
walkthrough?
Bobby
On Fri, Apr 3, 2020 at 11:05 PM Sam Just <sjust(a)redhat.com> wrote:
Here's Sage's initial writeup:
https://www.spinics.net/lists/ceph-devel/msg21635.html
-Sam
On Fri, Apr 3, 2020 at 12:12 PM Bobby <italienisch1987(a)gmail.com> wrote:
Hi,
I am trying to understand **Straw2** bucket used in **CRUSH algorithm**
of
**Ceph**. I have some specific questions. The code is given below:
**Questions:**
- Why there is a need of taking **log** of **hash value**?
- Is **x** the **placement ps** calculated by **crush_hash32_2**
function?
- What function **crush_ln()** in the given code
(mapper.c) is actually
computing? I am confused by the comment
**2^44*log2(input+1)**.
- Why there is a need of creating a negative
number based on **ln
(natural log)** of hash value?
Please help me understand these points.
Thanks in advance
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