[clug] kernel options

Daniel cottmain at plug.linux.org.au
Wed Aug 6 11:27:25 EST 2003

On Wed, 2003-08-06 at 07:15, Matthew Hawkins wrote: 
> Daniel said: ....
> >  a diagnosis of why I can't copy a really huge maildir directory.
> ... snip ...
> To your userspace cp(1) (or
> whatever) program, you're also limited by the per-process file descriptor
> limit (1024 by default) and any further limitations imposed by
> setrlimit(2) by your systems administrator.Unless you have some threaded version of cp(1) that's capable of shifting
> many files simultaneously, whatever the limit is is highly unlikely to be
> causing your problem.
> My guess would be, should you have some lame old filesystem like ext2 or
> ext3, with sufficient files in a single directory you're simply running
> into the fs's inability to quickly obtain the inodes for these files. 
> Does running ls(1) take a long time in this maildir?  If this is the case,
> you may like to consider using a modern filesystem like reiserfs or XFS or
> something.  This is true if either end (source, destination) fits this
> criteria.
> -- 
> Matt

Thanks very much Matt,
(good reply - hope my trim ok)
filesystem is reiserfs, Kernel 2.6test2, P4 2.4 512ram  (as of last
week's attempt to solve the issue (I did have some help)) 
/Inbox/subfolders# cp -av Dan01/* Dan02/
-su: /bin/cp: Argument list too long

du -sh Dan01
204M    Dan01

time ls -alh
real    0m2.272s

I read some suggestion to recompile the kernel eg:
"#define MAX_ARG_PAGES 32"
but I get nothing when I do
cat .config | grep MAX_ARG_PAGES   
//?? is there a similar option with a new name now?

I should explain why I want this in the first place: I was aiming to use
maildir with vfolders and backup the files past a certain date to cd
(cd system won't handle it as individual files so make image file of
directory, copy file to cd. When required mount cd, mount file to read
then aim the vfolder at them to find archived mails).
Maybe the directory is just way too big and the idea of backing up
maildirs in this way should be given up?


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