Re: Choosing and tuning Linux file systems

[Valerie Henson <val_henson@linux.intel.com>]

(Small accident occurred on Andreas' reply, restoring fsdevel and
quoting in entirety.)

On Mon, Jun 26, 2006 at 03:13:57AM -0600, Andreas Dilger wrote:
> On Jun 25, 2006  15:00 -0700, Valerie Henson wrote:
> > Lots of small files: reiser, ext2/3 with 1k blocks
> > More than ~32,000 files in one directory: XFS or reiser
> 
> This is actually "more than 32000 subdirectories in one directory".

Yeah, uh, dur.  Thanks!

> Unpatched ext3 is "good" up to 1M files and usable up to 10M regular
> files in a single directory.

Good to know the guidelines here.  Thanks!

-VAL

> > Choosing journaling mode in ext3
> >  - Default is "ordered", usually the right choice
> >  - "journal" is slower but guarantees data is on-disk as well
> 
> Also good for NFS server or mail spool running in "sync" mode (sync
> writes are linear into the journal).
> 
> >  - "writeback" is faster but may result in garbage/security leaks in
> >    your file data
> 
> ... after a crash
> 
> > Tuning reiser
> >  - I know nothing!!!  Help!
> 
> Tail packing saves space for small files, hurts performance somewhat.
> 
> > Laptop mode
> >  - I know almost nothing about this... some kind of write timeout?
> 
> Writes are cached until VM pressure forces them to disk (if disk is
> suspended), or there is a read which causes disk to spin up.  So,
> chance of data loss if laptop crashes or "suspends" w/o writing it.
> 
> 
> Cheers, Andreas
> --
> Andreas Dilger
> Principal Software Engineer
> Cluster File Systems, Inc.