Bug 2011600 - On EC reads always read entire stripe
Summary: On EC reads always read entire stripe
Keywords:
Status: NEW
Alias: None
Product: Red Hat Ceph Storage
Classification: Red Hat Storage
Component: RADOS
Version: 5.0
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: ---
: 8.0
Assignee: Neha Ojha
QA Contact: Manohar Murthy
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-10-06 20:34 UTC by Kyle Bader
Modified: 2023-07-06 17:52 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Issue Tracker RHCEPH-1991 0 None None None 2021-10-06 20:34:36 UTC

Description Kyle Bader 2021-10-06 20:34:08 UTC 
Description of problem:

On EC reads always read entire stripe, including padding. 

Version-Release number of selected component (if applicable):

ceph version 16.2.0-117.el8cp (0e34bb74700060ebfaa22d99b7d2cdc037b28a57) pacific (stable)

How reproducible:

Easy.

Steps to Reproduce:

* Create k=2 m=1 erasure code profile with stripe_unit set to 4M (implicit 8M stripe_width)
* Write 4M objects
* Read objects
* Observe 8M worth of reads

Actual results:

Entire stripe read (8M)

Expected results:

Only data read, not padding (4M)
Comment 1 RHEL Program Management 2021-10-06 20:34:15 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 Kyle Bader 2021-10-06 23:19:16 UTC 
Or really, no need to set the stripe_unit at all. Just write 4K objects, read them, and observe 8K worth of reads (4K of actual data on primary, 4K of padding on secondary).
Note You need to log in before you can comment on or make changes to this bug.