Re: [HTCondor-users] STARTD_ENFORCE_DISK_LIMITS problem with LVM and QEMU live migration

["Anderson, Stuart B." <sba@xxxxxxxxxxx>]

> On Jan 12, 2026, at 7:20âAM, Anderson, Stuart B. <sba@xxxxxxxxxxx> wrote:
> 
>> On Dec 29, 2025, at 10:34âAM, Anderson, Stuart B. <sba@xxxxxxxxxxx> wrote:
>> 
>> FYI, it looks like QEMU has an intersting limitation for Condor KVM EP with STARTD_ENFORCE_DISK_LIMITS enabled to use LVM, e.g.,
>> 
>> Dec 27 14:17:38 hov1 QEMU[3456386]: kvm: ../util/bitmap.c:167: bitmap_set: Assertion `start >= 0 && nr >= 0' failed.
> 
> FYI, it looks like this problem is more general and can be triggered by issuing lots of block device zero-fill requests (blkdiscard -z) during migration.

This is fixed for Proxmox [1] and I am now able to live migrate Condor EP VM that are aggressively using STARTD_ENFORCE_DISK_LIMITS. For non-PVE use of qemu the upstream patch is at [2]. 

[1] https://forum.proxmox.com/threads/live-migration-occasionally-fails-with-qemu-assertion-failure.177981/post-840602
[2] https://lore.kernel.org/qemu-devel/20260112152544.261923-1-f.ebner@xxxxxxxxxxx/T/

â
Stuart Anderson
sba@xxxxxxxxxxx