Bug 1827764

Summary: The documentation (in help and man page) for logical threads is incorrect
Product: Red Hat Enterprise Linux 8 Reporter: Andy Walsh <awalsh>
Component: vdoAssignee: corwin <corwin>
Status: CLOSED ERRATA QA Contact: Filip Suba <fsuba>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 8.3CC: awalsh
Target Milestone: rcFlags: pm-rhel: mirror+
Target Release: 8.0   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: 6.2.3.91 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-11-04 02:01:47 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 Andy Walsh 2020-04-24 18:11:47 UTC
Description of problem:
The current description of logical threads is not accurately describing the implementation.

Work is based on logical address, not hash.

Version-Release number of selected component (if applicable):
6.2.2.117

How reproducible:
100%

Actual results:
VDO Man page:
 processing based on the hash value computed from the block data. The value
 must be at least \*[logicalThreadsMin] and less than or equal to
 \*[logicalThreadsMax]. A logical thread count of
 \*[logicalThreadsBlockMapCacheSizeThreshold] or more will require explicitly
 specifying a sufficiently large block map cache size, as well.


vdo --help output:
 VDO processing based on the hash value computed from the block data.
 The value must be at least {min} and less than or equal to {max}. A
 logical thread count of {threshold} or more will require explicitly
 specifying a sufficiently large block map cache size, as well.



Expected results:
VDO Man page:
 processing based on the logical address. The value must be at least
 \*[logicalThreadsMin] and less than or equal to \*[logicalThreadsMax].
 A logical thread count of \*[logicalThreadsBlockMapCacheSizeThreshold] or
 more will require explicitly specifying a sufficiently large block map cache
 size.

vdo --help output:
 VDO processing based on the logical address. The value must be at least
 {min} and less than or equal to {max}. A logical thread count of
 {threshold} or more will require explicitly specifying a sufficiently
 large block map cache size.

Additional info:

Comment 3 Filip Suba 2020-08-21 08:06:55 UTC
Verified with vdo-6.2.3.114-14.el8.

--vdoLogicalThreads <threadCount>
                        Specifies the number of threads across which to
                        subdivide parts of the VDO processing based on the
                        logical address. The value must be at least 0 and less
                        than or equal to 60.

Comment 6 errata-xmlrpc 2020-11-04 02:01:47 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (kmod-kvdo bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:4551