Hi all, I am doing some research about "the best way" to give a partition to Oracle. I found this surprising and you may too, it is quite amusing: http://jrs-s.net/2013/05/17/kvm-io-benchmarking/ But here’s the big surprise – if we set up a ZVOL, then format it with ext4 and put a .qcow2 on top of that… it performs as well, and in some cases better than, the raw zvol itself did! As odd as it sounds, this leaves qcow2-on-ext4-on-zvol as one of our best performing overall storage methods, with the most convenient options for management. It sounds like it’d be a horrible Rube Goldberg, but it performs like best-in-breed. Who’d’a thunk it? According to the benchmark you have this layering: - qcow2 (virtual disk) as a file on an - ext4 filesystem formatted on a - zvol created on a - raw partition performing better than a raw partition! But - zvol created on a - raw partition is "not worth the hassle". Any thoughts and experiences? I want to give a disk via iSCSI to Oracle (Avi knows more;-) and look for the best setup. The iSCSI target is FreeBSD which can export files as block devices or zvols or raw disks or mirrored disks or other exotic GEOM devices on top of raw disks. According to the benchmark above, a file exported as a blockdevice on top of a zvol could be better than an exported disk.. Could this be true? Regards Peter