Red Hat Bugzilla – Bug 1464739
Cache & thin pool target always commits data even for unused devices
Last modified: 2017-06-25 05:41:47 EDT
Description of problem:
When user creates thin-pool with unused thin LV, or caches a volume, then every call a flushing 'dmsetup status' cause very small i/o batch to pass on actual real device.
This is not a big deal in case performance, but it prevents unused 'devices' to stay in sleep eventually wakes them up whenever admin runs:
As a workaround to keep disks sleeping - user may 'add --noflush' arg...
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. create thinLV (lvcreate -L10 -V10 -T vg/pool -n thinLV) (or cache some LV)
2. iostat -d 1
3. observe i/o load with every 'dmsetup status' call