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x86: 0.985
architecture: 0.933
virtual: 0.890
debug: 0.887
performance: 0.877
network: 0.866
device: 0.747
graphic: 0.736
peripherals: 0.734
mistranslation: 0.713
VMM: 0.684
KVM: 0.650
hypervisor: 0.632
kernel: 0.625
PID: 0.615
semantic: 0.589
ppc: 0.541
user-level: 0.535
register: 0.484
files: 0.454
socket: 0.429
arm: 0.363
assembly: 0.320
vnc: 0.318
risc-v: 0.277
i386: 0.275
TCG: 0.265
boot: 0.237
permissions: 0.211
--------------------
virtual: 0.994
debug: 0.983
x86: 0.982
user-level: 0.643
hypervisor: 0.483
TCG: 0.134
kernel: 0.097
KVM: 0.074
VMM: 0.029
files: 0.020
register: 0.017
PID: 0.017
semantic: 0.009
performance: 0.007
architecture: 0.004
network: 0.004
device: 0.004
socket: 0.003
risc-v: 0.002
graphic: 0.002
peripherals: 0.002
boot: 0.002
assembly: 0.002
permissions: 0.001
ppc: 0.001
vnc: 0.001
mistranslation: 0.000
i386: 0.000
arm: 0.000
Sporadic input / output error — x86-64 linux guest
** Setup: **
→ Host
Qemu version 2.4.0.1
Linux: 4.1.1 (Debian 8.2, GCC 4.9.2, x86_64)
filesystem ext3 and ext4
→ Guests (3 VMs)
architecture x86_64, Linux 3.16.0-4-amd64 (Debian 7.6)
virtual disk qcow2, uncompressed
guests filesystem ext3
virtual disks size: VM1: 3GB, VM2: 5GB, VM3: 250GB
→ Network
bridge (br0) and tap interfaces.
** Command line **
For all 3 VMs, the command line is similar to the following. Only RAM size and ID ("109") are changed.
/usr/local/bin/qemu-system-x86_64 -hda /media/raid1/qemu-109 -m 8G -smp 4 -enable-kvm \
-netdev bridge,id=br109 -device virtio-net-pci,netdev=br109,id=nic0,mac=00:00:00:00:01:09 \
-k it -daemonize
** Problem **
Sporadic, unexplained input output error.
When I try to SSH to one of the instances, most of the times everything just works fine. Some other times, the SSH connection can be established, but as I interact with the guests via SSH (ls, cd, top) the guest reports "input / output error" on the SSH console. Sometimes, the SSH daemon on the guest answers "/bin/bash input output error". Sometimes the SSH client answers that the connection has been dropped by the host.
When this happens, the web services I run on the VMs get unreachable, the VMs themselves are unreachable/unusable via SSH as described, and after killing the relative qemu processes and restarting the VMs, no recent logs are registered on /var/logs, arguably since the time of the crash.
This only happens to one VM at a time, independently. The other VMs appear to run fine when one VM encounters the problem.
I which instructions to further debug this.
Looking through old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays?
[Expired for QEMU because there has been no activity for 60 days.]
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