Hi Szabolcs,

The reason for the O_SYNC option in the open on the NTFS device was
mainly to ensure Wubi was writing data back to NTFS. Wubi relies on a
loopback'd file system in a file in the ntfs fileystem, and hence there
was a lot of latency between a write to the loopback, down through the
ntfs filesystem via fuse.  We were seeing problems with power-outages
causing systems to become unbootable due to the write-back cached data
latencies.  One hacky approach was to tweak the vm settings to force
writebacks as soon as possible to avoid blocks hanging around in the
cache - this was a hack and not an elegant solution as it applies to all
file systems across the board.  Hence I added the O_SYNC option to ntfs-
3g avoid this hack.

Basically we ultimately need a method of ensuring ntfs data and metadata
is sync'd to disk asap to keep Wubi as robust as possible.  As for
performance penalty, I have also benchmarked the SYNC mode of operation
and it is inline with the figure your report. This is probably OK for
Wubi since most of the I/O operations are read and not writes, and I
suspect robustness is more important than speed - but it will probably
be an choice that the Wubi user can make.

Colin.

-- 
wubi install unusable - Buffer I/O error on device loop0
https://bugs.launchpad.net/bugs/204133
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to