On 4/26/12, Boris Epstein borepstein@gmail.com wrote:
Hello all,
I am running VirtualBox 4.1 on CentOS 6 and I got this warning that putting your VM's into an XFS filesystem is risky. I have also heard some rumors on the net to this effect. Does anyone know in more detail what's behind those rumors?
I came across the same warnings while looking up on using XFS as the fs on storage nodes. IIRC it has to do with caching and flushing to disk.
From what I understood:
VM caches writes before sending it to the virtual disk. Host's XFS does delay logging to address performance issue before sending it to the HDD HDD caches writes for performance and may not respect commands that demand it turn off caching and flush writes.
If a power cut occurs, in the absence of a BBU HBA, it seems that it is indeterminable if the last few writes had been committed and in what sequence and usually means a corrupted VM.