extremely slow copy speed (50k/s)
Ron Leach
ronleach at tesco.net
Fri Feb 18 15:17:27 UTC 2011
vinícius mota wrote:
>
> Briefly, the problem is that the copy speed between the partition in
> which I am running my Fedora and another partition where I store backup
> data is now 50K/s, which is extremely slow by any standart (it has been
> usually around 10M/s, almost 200 times faster).
Wow, that's slow between partitions.
> One of the disks is partitioned between two operational
> systems, Fedora 14 64 and Windows 7 64, and the other disk contains the
> above referred partition where I store my backups (I call it backup
> disk).
> I login into the windows and
> made a copy of some AVI files (3G approx) to the backup disk, which went
> normally
So hardware is ok and, also, Windows' disk handlers are probably ok.
> I move data within the backup iself disk using windows also without any
> problem.
I don't think this would move the files, would it? Wouldn't the
directory entries, only, change? Could you try a 'copy' within the
backup (under windows), just to be sure. Preferably something quite
large.
> I try therefore to make the inverse process, a copy from the
> backup disk into my home folder in Fedora. It went normally, copying 4 G
> also within few seconds, actually with an excellent speed of 50M/s.
>
Good
> [Google might show] one cause could be that the source file system (in my
> case the Fedora home folder) would be near its full capacity.
I wouldn't have thought so; to me it looks much more like a data
problem on the destination, or a problem in the F14 disk handlers (but
would have been quite widely reported, by now?).
It is clear that you have been using Fedora for some time so I expect
you have already done what I will ask, but you did not say. My first
thought on reading the symptoms was that, possibly, the backup
partition is getting full with 'wastebasket/recyclebin' files, which
have to be 'deleted for real' before the 'new files' that you are
copying can be copied. And, maybe, Windows is a little bit faster at
that than F14 NTFS handlers (maybe). Maybe F14 is 'deleting for real'
at a single sector at a time, or something?
I wonder, also, if the number of IO reads and writes on the backup
disk could be measured and reported; that might provide a clue as to
whether there is excessive processing, or whether there is otherwise
some software delay. But I do not know how to measure IO transactions.
>
> He is the line of my /etc/fstab file which defines my backup disk, with
> the label common
>
> LABEL=common /home/vinicius/Desktop/common ntfs
> auto,user,sync 0 0
>
Am I correct in thinking that 'sync' disables write-caching? It might
be interesting to change that, and see if performance is still just as
bad.
Best of luck, Ron
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