Hello, i´ve done 2 vm with qcow2 disks and created them with qemu-img with prealloc=metadata. Virt-Manager shows me under the performance settings for the Storage, Cache= Hypervisor Default IO= Hypervisor Default Is this the best setting? Or do i choose "native" IO on prealloc=metadata created disks? And do i have to change Cache too? The Virtualisation Host is gento linux, the qcow2 files are stored on a xfs partition, qemu is build with "xfs" Flag. thanks for hints and tipps marko -- zbfmail - Mittendrin statt nur Datei! OpenDKIM, SPF, DSPAM, Greylisting, POSTSCREEN, AMAVIS, Mailgateways Mailfiltering, SMTP Service, Spam Abwehr, MX-Backup, Mailserver Backup Redundante Mailgateways, HA Mailserver, Secure Mailserver