Hi Granwille! About the READ/WRITE performance, as Levin suggested, check the XML of virtual machines looking at disk/device section. Look for io='io_uring'.
As stated here: https://github.com/apache/cloudstack/issues/4883 CloudStack can use io_uring with Qemu >= 5.0 and Libvirt >= 6.3.0. I tried to do some tests at some points like your environment. ###################################### VM in NFS Primary Storage (Hybrid NAS) Default disk offering, thin (no restriction) <devices> <emulator>/usr/bin/qemu-system-x86_64</emulator> <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none' io='io_uring'/> <source file='/mnt/74267a3b-46c5-3f6c-8637-a9f721852954/fb46fd2c-59bd-4127-851b-693a957bd5be' index='2'/> <backingStore/> <target dev='vda' bus='virtio'/> <serial>fb46fd2c59bd4127851b</serial> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk> fio --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=/tmp/random_read_write.fio --bs=1300m --iodepth=8 --size=6G --readwrite=randrw READ: 569MiB/s WRITE: 195MiB/s ###################################### VM in Local Primary Storage (local SSD host) Default disk offering, thin (no restriction) <devices> <emulator>/usr/bin/qemu-system-x86_64</emulator> <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none' io='io_uring'/> <source file='/var/lib/libvirt/images/d100c55d-8ff2-45e5-8452-6fa56c0725e5' index='2'/> <backingStore/> <target dev='vda' bus='virtio'/> <serial>fb46fd2c59bd4127851b</serial> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> fio --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=/tmp/random_read_write.fio --bs=1300m --iodepth=8 --size=6G --readwrite=randrw First run (a little bit slow if using "thin" because need to allocate space in qcow2): READ: bw=796MiB/s WRITE: bw=265MiB/s Second run: READ: bw=952MiB/s WRITE: bw=317MiB/s ############################## Directly in local SSD of host: fio --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=/tmp/random_read_write.fio --bs=1300m --iodepth=8 --size=6G --readwrite=randrw READ: bw=931MiB/s WRITE: bw=310MiB/s OBS.: parameters of fio test need to be changed to test in your environment as it depends on the number of cpus, memory, --bs, --iodepth etc. Host is running 5.15.0-43 kernel, qemu 6.2 and libvirt 8. CloudStack is 4.17.2. So, VM in local SSD of host could have very similar disk performance from the host. I hope this could help you! Thanks. > -- __________________________ Aviso de confidencialidade Esta mensagem da Empresa Brasileira de Pesquisa Agropecuaria (Embrapa), empresa publica federal regida pelo disposto na Lei Federal no. 5.851, de 7 de dezembro de 1972, e enviada exclusivamente a seu destinatario e pode conter informacoes confidenciais, protegidas por sigilo profissional. Sua utilizacao desautorizada e ilegal e sujeita o infrator as penas da lei. Se voce a recebeu indevidamente, queira, por gentileza, reenvia-la ao emitente, esclarecendo o equivoco. Confidentiality note This message from Empresa Brasileira de Pesquisa Agropecuaria (Embrapa), a government company established under Brazilian law (5.851/72), is directed exclusively to its addressee and may contain confidential data, protected under professional secrecy rules. Its unauthorized use is illegal and may subject the transgressor to the law's penalties. If you are not the addressee, please send it back, elucidating the failure.
