Description of problem: install rhel5.9.64(guest) in rhel.59.64(host), when using qcow2 image with virtio interface, it will take too long time(about 1 hour) . FYI:1. the hardware is the newest amd machine. 2. when i install the guest using raw format disk with ide interface, about 35 mins can finished the installation. Version-Release number of selected component (if applicable): How reproducible: 100% Steps to Reproduce: 1.install rhel5.9-64(guest) in rhel5.9-64(host),using qcow2 virtio image. 2.t 3. Actual results: about 1 hours, slowly than ide Expected results: about 30mins , should be faster than ide Additional info: host info: kernel:kernel-2.6.18-339.el5 kvm:kvm-83-259.el5 cpuinfo: processor : 15 vendor_id : AuthenticAMD cpu family : 16 model : 9 model name : AMD Opteron(tm) Processor 6128 stepping : 1 cpu MHz : 2000.046 cache size : 512 KB physical id : 2 siblings : 8 core id : 3 cpu cores : 8 apicid : 39 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow rep_good constant_tsc nonstop_tsc amd_dcm pni cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt nodeid_msr bogomips : 4000.14 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm stc 100mhzsteps hwpstate [8]
yunpingzheng, Can you please try to see if it is the qcow vs raw, or virtio vs. ide. Thanks, Ronen.
Ronen virtio qcow2 (about 50-60 mins) raw (about 25 mins) ide qcow2 (about 60 mins) raw (about 30 mins)
Yes, cluster allocation in qcow2 under RHEL 5 is slow. We know it and there's no justifiable way to fix it. Unless it's a clear regression from the previous minor release, qcow2 performance issues won't be considered to be fixed in RHEL 5. To work around it, use preallocation or raw images if you can.