On Thursday 21 July 2005 22:10, Jörg Rennefeld wrote:
On Thursday 21 July 2005 14:59, Jörg Rennefeld wrote:
Hi,
I have the following problem: I can't create files bigger than 2GB on
the Host Disk from inside a UML.
Is the Hostfs driver limited to 2GB? I always get the error message:
file size limit exceeded
I'm gonna look, I guess that this may be true, but should be trivially
fixable...
However, the code seems correct, so a question: which UML release are you
using?
I am using a UML release delivered with a Debian server project from a
german Computer Magazine.
After a recent Kernel update a "uname -r" inside the UML returns:
2.4.31-bs2-pre11
I also tried Kernel 2.6.12 both show a similar behavior. The command:
"dd if=/dev/zero of=test.img bs=1024 count 3000k" returns the message:
"File size limit exceeded". The file created by dd has exactly the size
2147483647 bytes.
Have you verified if the problem lays into UML or into the guest distribution?
I.e. if the "dd" version you're using is not up-to-date, the program itself
won't allow that (and until very recently, i.e. 2 months ago, wget has this
problem - don't know if that has yet been fixed).
And since you're talking about Debian, that seems likely. Strace the offending
program, grep for "open" and verify that O_LARGEFILE is passed between the
params. Or try doing that command on the root_fs directly, here's the road to
do the test, which is done via creation of a sparse file:
dd if=/dev/zero of=test.img bs=$((1024*1024)) seek=$((3*1024) count=1
If this doesn't work, then your guest fs has a broken dd (and probably glibc
too) and you should upgrade.
It's even possible that the host system itself is too outdated and hasn't
support for this stuff - give all version information, please.
First I will try to give you some version information. The host system
runs debian sarge with the 2.4.31 Kernel, dd ist verion 5.2.1 on the
host and also in the UML. The UML runns Kernel 2.6.l2 with skas,tt and
hosfs.
I did some more tests today an I am pretty sure this is a hostfs issue.
I'll try to explain why i think so. I first encountered the file size
problem when I tried to download a big file with the mldonkey running
inside the UML. Mldonkey writes the via on the host disk via hostfs and
this works good with files smaller than 2GB.
I use dd for testing and it shows the same behavior as the mldonkey.
Today used mldonkey and dd directly on the host and both were able to
create files >2GB. Then I resized the UML filesystem to 3GB and used dd
and mldonkey inside the UML on the filesystem, not on hostfs. Again both
programms were able to create files > 2GB.
I also tried your suggestion and used strace with dd and it returned:
open("test.img", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 1
Since I am no linux Expert and the programms I used seem to be ne newest
versions I don't know what else I can try.
I appreciate your time and hope you can give me some hints.
thanks,
Jörg Rennefeld
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