Similar to the FS-Mark test where the Wubi installation ended up being much faster than Ubuntu 10.10 running on a real partition with the EXT4 file-system, the PostgreSQL server had more than 24 times the number of transactions per second when Ubuntu Maverick Meerkat was installed to the drive via Wubi on Windows 7 x64.
Yep, this Wubi performance situation looks just like the Ubuntu virtual machine disk sync problem we found 13 months ago that was further explored by Matthew Tippett.
With the PostMark disk benchmark, the real Ubuntu 10.10 installation that occupied the entire disk was more than six times faster than the Wubi installed version.
Installing Ubuntu via the Windows Wubi installer sure is convenient if you are just thinking about toying with an Ubuntu Linux desktop for the first time, but if you plan to use this Linux desktop on a routine basis or the file-system performance and integrity is of any importance to you, the best path is to just perform an Ubuntu installation to a true disk partition. The disk performance via this disk image on the NTFS file-system was not affected in all benchmarks, like with IOzone, but when it came to running Gzip compression or PostMark there certainly was a slowdown. With SQLite, PostgreSQL, and FS-Mark the Wubi setup was dramatically faster, which does raise concerns over data integrity with some operations likely being carried out a-synchronously or batched. The state of our Wubi installation was also rather ideal with the testing having been done on a clean Microsoft Windows 7 installation where the NTFS file-system was not fragmented, which would further slow down the Ubuntu Wubi-ized installation.