Messages in this thread | | | Date | Fri, 24 Feb 2006 11:29:57 -0500 | From | Theodore Ts'o <> | Subject | Re: question about possibility of data loss in Ext2/3 file system |
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On Fri, Feb 24, 2006 at 08:46:24AM +1300, Sam Vilain wrote: > Theodore Ts'o wrote: > >>Also, the scheme you mentioned is just for new file creation. What > >>will happen if I want to update an existing file? Say, I open file A, > >>seek to offset 5000, write 4096 bytes, and then close. Do you know how > >>ext2/3 handle this situation? > >If you have a power failure right after the close, the data could be > >lost. This is true for pretty much all Unix filesystems, for > >performance reasons. If you care about the data hitting disk, the > >application must use fsync(). > > I always liked Sun's approach to this in Online Disk Suite - journal at > the block device level rather than the FS / application level. > Something I haven't seen from the Linux md-utils or DM.
You can do data block journalling in ext3. But the performance impact can be significant for some work loads. TNSFAAFL.
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