Hello all,
I've been testing the NAS performance of ext3/Openfiler 2.2 against
NTFS/WinXP and have found that NTFS significantly outperforms ext3 for
video workloads. The Windows CIFS client will attempt a poor-man's
pre-allocation of the file on the server by sending 1-byte writes at
128K-byte strides, breaking block allocation on ext3 and leading to
fragmentation and poor performance. This will happen for many
applications (including iTunes) as the CIFS client issues these
pre-allocates under the application layer.
This is being worked on already. XFS has a per-filesystem ioctl, but
we want to create a filesystem-independent system call,
sys_fallocate(), that would wired into the already existing
posix_fallocate() function exported by glibc.