Synchronising between a Linux box and a FAT32 filesystem (in my case a
2.5" portable HDD) using Unison:
1. Enable pretendwin and fastcheck
2. Modify any file in the repository (or touch a temporary file)
3. Resynchronise (takes about half an hour)
4. Resynchronise again (takes 20 seconds!)
5. Umount and replug the portable HDD, it still only takes 20 seconds.
I found while experimenting with a trivial repository that:
* You do need pretendwin when running the Unix Unison client on a
Windows filesystem (FAT32, NTFS), and
* Unison appears to only use the resulting pseudo-inode numbers
after the second synchronisation that causes a change in the
repository.
I believe that Unison is doing this:
1. Copied over a new repository image, and wrote archive files (in
~/.unison) without pseudo-inode numbers for the FAT32 drive.
2. During a resynch with no changes, Unison read every file in full,
but did not write the updated archive file (because there were no
changes).
3. A resynch with a single change caused Unison to read every file in
full and write the newly updated archive file, including the
pseudo-inodenumbers.
4. Subsequent synchs succeed in fastchecking.
Douglas Royds wrote:
I'm successfully synching my (44GB of) photos, videos, etc to my
portable HDD, but ...
1. It's taking forever (half an hour to check an already-synchronised
tree, or about 24MB/sec)
2. It is copying files when the permissions disagree, even though I
have perms = 0
In short, Unison seems to be ignoring these preferences:
* fastcheck = true
* perms = 0
I tried setting them on the command-line, and also tried a run with
-pretendwin, just in case:
$ unison Documents -perms 0 -fastcheck true
$ unison Documents -perms 0 -fastcheck true -pretendwin
No cigar.
Suggestions?
Douglas.
Documents.prf:
include default
root = /home/roydsd/Documents
root = /media/Port-Docs/Documents
mountpoint = Pictures
perms = 0
backup = Name *
backupdir = /media/Port-Docs/Backups
default.prf:
log = true
logfile = /home/roydsd/.unison/unison.log
auto = true
addprefsto = default
fastcheck = true
ignore = Name {.*~,*~,.#*}
ignore = Name {,.}*{.swp}
ignore = Name {Thumbs.db}
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