I found this thread from a few months ago that seems to have been
started by someone with the same problem I have, but it was not resolved:
https://www.redhat.com/archives/ext3-users/2005-March/msg00000.html
I have been trying to speed up my boot times and I notice that a lot of
time is spent waiting on IO. Even with readahead-list precacheing
files, it is reading at less than 1/4 of my disk's maximum sequential
throughput. I feel this is because the files are scattered all around
the disk, which causes a lot of seeking.
I am looking for a way to defragment the disk such that the files needed
for boot are all packed sequentially at the beginning of the disk, so
that readahead-list can read them in much faster.
During that previous thread, it was stated that it was impossible to
have defrag work safely on an ext3 partition. I do not see why this is
so. If ext2 could be given a journal to make it crash resistant, then
why can't defrag be given the same thing?
Another comment was made saying that such a defragger could not possibly
be done only in userspace. Unless you're talking about online
defragmentation, then manipulating the filesystem offline to repack it
is entirely possible from userspace.
Is there still no way to do what I am trying?
P.S. Please CC me on replies, as I am not subscribed.
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