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<div>Hi, </div>
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<div>we just set up a new 4.1.2 OVirt cluster. It is a quite normal</div>
<div>HDD/XFS/NFS stack that worked quit well with 4.0 in the past. </div>
<div>Inside the VMs we use XFS too.</div>
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<div>To our surprise we observe abysmal high IO during mkfs.xfs </div>
<div>and fstrim inside the VM. A simple example:</div>
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<div>Step 1: Create 100G Thin disk</div>
<div>Result 1: Disk occupies ~10M on storage</div>
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<div>Step 2: Format disk inside VM with mkfs.xfs</div>
<div>Result 2: Disk occupies 100G on storage</div>
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<div>Changing the discard flag on the disk does not have any effect.</div>
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<div>Am I missing something?</div>
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<div>Best regards.</div>
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<div>Markus</div>
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