﻿id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host
14982,VBoxManage bandwidthctl breaks on low values => fixed in SVN/next maintenance,dimaqq,,"Setting disk bandwidth to a really low value (e.g. 1K) appears to turn off the throttle entirely, and throttle can only be re-enabled by vm power cycle (reboot is not enough).

Test:
echo 3 > /proc/sys/vm/drop_caches
time dd if=/dev/sdb of=/dev/null bs=1M count=10

Setup:
Cloned a VM
Set up IO group with 10M limit
Attached existing 2nd SCSI disk to group

Test sequence:
set limit to 1M
booted up vm
test result 1.2 MB/s
repeated test (to be sure)
test result 1.2 MB/s

set limit to 1K
test result 91.9 MB/s

set limit to 1M
test result 156 MB/s
repeated test
test result 82.0 MB/s

rebooted vm
test result 82.0 MB/s

shut down vm
started vm
test resut 1.2 MB/s


Summary:
It doesn't matter if low limit was set at runtime or in advance
Critical value is between 210K (broken) and 225K (works)
VM shutdown is needed to recover throttling


",defect,closed,virtual disk,VirtualBox 5.0.12,fixed,,,other,other
