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There is a workaround: edit the /etc/vdoconf.yml file, and change the value of the "blockMapPeriod" parameter. After this, the "vdo status" command should reflect the newly configured value, which can then be enabled by running "vdo stop --name=<vdoname>", then "vdo start --name=<vdoname>".
I need to verify the valid range of the blockMapPeriod; I believe it's 1 to 16380, but in practice, the blockMapPeriod value should be adjusted down from its maximum, with testing to ensure that there's no significant performance degradation from the increased frequency of updates to disk from the block map cache.
(In reply to Bryan Gurney from comment #2)
> There is a workaround: edit the /etc/vdoconf.yml file, and change the value
> of the "blockMapPeriod" parameter. After this, the "vdo status" command
> should reflect the newly configured value, which can then be enabled by
> running "vdo stop --name=<vdoname>", then "vdo start --name=<vdoname>".
>
> I need to verify the valid range of the blockMapPeriod; I believe it's 1 to
> 16380, but in practice, the blockMapPeriod value should be adjusted down
> from its maximum, with testing to ensure that there's no significant
> performance degradation from the increased frequency of updates to disk from
> the block map cache.
We should never be telling people to manually edit that file. We even added in a comment at the top of the file to not manually edit. So I'm not sure this is a very good workaround to tell people to do.
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, 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/RHEA-2018:0871
Description of problem: Using "vdo modify" with argument "--blockMapPeriod" runs without error but does not change the block map period: # vdo create --device /dev/sdc --name vdo --blockMapPeriod 10 Creating VDO vdo Starting VDO vdo Starting compression on VDO vdo VDO instance 26 volume is ready at /dev/mapper/vdo VDO volume created at /dev/mapper/vdo # vdo status --all | grep "Block map period" Block map period: 10 # vdo modify --name vdo --blockMapPeriod 500 # echo $? 0 # vdo status --all | grep "Block map period" Block map period: 10 # vdo create --device /dev/sdc --name vdo Creating VDO vdo Starting VDO vdo Starting compression on VDO vdo VDO instance 27 volume is ready at /dev/mapper/vdo VDO volume created at /dev/mapper/vdo # vdo status --all | grep "Block map period" Block map period: 16380 # vdo modify --name vdo --blockMapPeriod 500 # echo $? 0 # vdo status --all | grep "Block map period" Block map period: 16380 Version-Release number of selected component (if applicable): 6.1.0.0.6 How reproducible: 100% Steps to Reproduce: 1. vdo create --device /dev/sdc --name vdo 2. vdo status --all | grep "Block map period" 3. vdo modify --name vdo --blockMapPeriod 500 4. vdo status --all | grep "Block map period" Actual results: No change of block map period value Expected results: Changed vdo block map period value Additional info: