Performing a data copy function of a preallocated volume, such as creating a template, results in a slowdown of all i/o to/from the NFS server in question. The NFS file systems are V3, with the default mount options provided by RHV.
On the SPM host, MiscFileReadException read timeouts in VDSM and high repoStats 'delay' times are seen, Storage Domains become 'INVALID', and VM's become unresponsive.
All storage domains on the same NFS server are affected.
This can be replicated by manually running;
# qemu-img convert -p -t none -T none -f raw <src path> -O raw -o preallocation=falloc <dest path>
- Removing "-o preallocation=falloc" circumvents the problem, but the result is a sparse file instead of a preallocated file.
- Red Hat Virtualization (RHV) 4.3.9
- Red Hat Virtualization Hypervisor (RHVH) 4.3.9;
- NFS v3 storage domains
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