On Thu, May 20, 2021 at 17:14:31 +0200, Pavel Hrdina wrote: > The default value hard-coded in QEMU (64KiB) is not always the ideal. > Having a possibility to set the cluster_size by user may in specific > use-cases improve performance for QCOW2 images. > > QEMU internally has some limits, the value has to be between 512B and > 2048KiB and must by power of two, except when the image has Extended L2 > Entries the minimal value has to be 16KiB. > > Since qemu-img ensures the value is correct and the limit is not always > the same libvirt will not duplicate any of these checks as the error > message from qemu-img is good enough: > > Cluster size must be a power of two between 512 and 2048k > > Resolves: https://gitlab.com/libvirt/libvirt/-/issues/154 > > Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx> > --- > > Changes in v2: > - Documentation now describes only what can be affected by changing > cluster_size. Reviewed-by: Peter Krempa <pkrempa@xxxxxxxxxx>
