Hello Since quite some time, I'm seeing sporadic I/O errors in guests running ontop of virtio_blk devices. The information I have is quite bare: guest usually shows something like: Feb 6 02:47:34 hobbit kernel: end_request: I/O error, dev vda, sector 9786968 Feb 6 02:47:34 hobbit kernel: Buffer I/O error on device vda7, logical block 473367 Feb 6 02:47:34 hobbit kernel: lost page write due to I/O error on vda7 Feb 6 02:47:34 hobbit kernel: Aborting journal on device vda7. Feb 6 02:47:35 hobbit kernel: ext3_abort called. Feb 6 02:47:35 hobbit kernel: EXT3-fs error (device vda7): ext3_journal_start_sb: Detected aborted journal Feb 6 02:47:35 hobbit kernel: Remounting filesystem read-only After this point, the system is still live but the corresponding block device stops working. I can umount the device, but any attempt to remount it tells the device is *busy*, and using, say, cfdisk on it (just starting, attempting to READ the partition table) results in a kernel OOPS after about a 2 mins of inactivity. At which time host displays a series of vcpu not ready for apic_round_robin messages (about 20 of them). I'm trying to capture the OOPS right now. But obviously the problem is elsewhere, since that OOPS is far after the original issue (the I/O errors). It happens sporadically, sometimes the guest is running for a week, sometimes (as here) it crashed after several hours of uptime. It does not relate to system activity either, as far as I can see -- happens on either high or slightly-loaded system, and may happen on mostly idle guest system while another high-loaded guest is running at the same time. The host is running 2.6.27.10 x86-64 on a AMD Phenom 9750 processor, AMD 780G/SB700 chipset. Using stock kvm modules. Userspace is 32bits kvm-83. Guests are linux systems running 2.6.27.10 or .14, 32bits, uniprocessor. After seeing this link -- https://bugs.launchpad.net/ubuntu/+source/kvm/+bug/246175 , I disabled cpufreq on host. Bit it didn't help. The issue persists since about a month or two (difficult to say as the problem is very sporadic). I *think* kvm-72 (for example) exposed the same problem on this host/guest combination, but I'm not sure. Any pointers on how to debug the prob, or, even better, if it's a known issue, is very welcome -- this is a production system and it becomes quite.. unstable. Thanks! /mjt -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
