Bug 2062581

Summary: [Docs] Add "librbd persistent write log cache to reduce latency" section to 5.1 (GA) Release Notes
Product: [Red Hat Storage] Red Hat Ceph Storage Reporter: Congmin <congmin.yin>
Component: DocumentationAssignee: Ranjini M N <rmandyam>
Documentation sub component: Release Notes QA Contact: Preethi <pnataraj>
Status: CLOSED CURRENTRELEASE Docs Contact:
Severity: high    
Priority: unspecified CC: guifeng.tang, pnataraj, rmandyam
Version: 5.1   
Target Milestone: ---   
Target Release: 5.1   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2022-04-05 11:03:19 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Congmin 2022-03-10 08:06:11 UTC 
Describe the issue:
Add a new feature "Persistent Write Log Cache" section to the RHCS 5.1 (GA) Release Notes. 

Describe the task you were trying to accomplish:
N/A

Suggestions for improvement:
N/A

Document URL:
RHCS 5.1 (GA) Release Notes

Chapter/Section Number and Title:
"librbd persistent write log cache to reduce latency"



Product Version:
5.1 (GA)

Environment Details:
N/A

Any other versions of this document that also needs this update:
N/A

Additional information:
Add the following statement to the new "librbd persistent write log cache to reduce latency" section in the RHCS 5.1 (GA) Release Notes:

"With this release, the new librbd plugin named Persistent Write Log Cache (PWL) provides a persistent, fault-tolerant write-back cache targeted at PMEM or SSD devices. It can greatly reduce latency, also improves performance at low io_depths.

This cache uses a log-ordered write-back design which maintains checkpoints internally so that writes that get flushed back to the cluster are always crash consistent. Even if the client cache is lost entirely, the disk image is still consistent, but the data will appear to be stale."

User guide:
https://bugzilla.redhat.com/show_bug.cgi?id=2058537
Comment 1 RHEL Program Management 2022-03-10 08:06:16 UTC 
Please specify the severity of this bug. Severity is defined here:
https://bugzilla.redhat.com/page.cgi?id=fields.html#bug_severity.
Comment 2 Guifeng 2022-03-17 07:01:00 UTC 
Looks this ticket status is still assigned, will it change to close or some other status, to indicate that RHCS5.1 release note team has confirmed the add of this feature?