Author: eelco Date: 2010-06-13 23:36:55 +0000 (Sun, 13 Jun 2010) New Revision: 22248
You can view the changes in this commit at: https://svn.nixos.org/viewvc/nix?rev=22248&view=rev Modified: nixos/branches/boot-order/modules/virtualisation/qemu-vm.nix Log: * Use writeback caching for virtual disks instead of writethrough caching. This makes a huge performance difference (e.g. from 4 MB/s `dd' throughput to 140 MB/s on the Hydra machines). As the QEMU manual says: "Some block drivers perform badly with ?\226?\128?\152cache=writethrough?\226?\128?\153, most notably, qcow2." Changes: Modified: nixos/branches/boot-order/modules/virtualisation/qemu-vm.nix =================================================================== --- nixos/branches/boot-order/modules/virtualisation/qemu-vm.nix 2010-06-13 20:59:49 UTC (rev 22247) +++ nixos/branches/boot-order/modules/virtualisation/qemu-vm.nix 2010-06-13 23:36:55 UTC (rev 22248) @@ -128,7 +128,7 @@ -m ${toString config.virtualisation.memorySize} \ -no-kvm-irqchip \ -net nic,vlan=0,model=virtio -net user,vlan=0 -smb / \ - -drive file=$NIX_DISK_IMAGE,if=virtio,boot=on,werror=report \ + -drive file=$NIX_DISK_IMAGE,if=virtio,boot=on,cache=writeback,werror=report \ -kernel ${config.system.build.toplevel}/kernel \ -initrd ${config.system.build.toplevel}/initrd \ ${qemuGraphics} \ _______________________________________________ nix-commits mailing list [email protected] http://mail.cs.uu.nl/mailman/listinfo/nix-commits
