A journalling file system is almost always a better idea and will
help with this, but probably won't solve all your problems.  VXFS is
a good choice, but I like the LSCI products like QFS as well.  Sun
has just recently aquired LSCI earlier this year.

The real problem I see is that if you do suceed in a backup, you will
have a really hard time restoring this data if you loose the whole
filesystem.  The inode creation is relatively slow and will take
forever if at all for this number of small files.  A block level
backup is a much better solution and would bypass the small file
problem caused by file system overhead.

A full block level backup with the incrementals handled with some
variant of snapshot technology would probably be the most efficient,
but you're then relying on the RAID technology for the incrementals.

I believe there are block level incremental backups out there, but
I'm not sure if Legato is one of the vendors.

If this sounds like something your looking for, let me know and I'll
get the product info for you.


  --Jason Stege
  Independant Consultant

--- Stuart Lamble <Stuart.Lamble AT ITS.MONASH.EDU DOT AU> wrote:
> Since there seems to be a certain amount of interest on the list,
> here's a list of things we have (and have not :) tried to date.
> First,
> a quick rundown on the filesystem:
>
>   * 522 GB hardware RAID partition.
>   * Approximately 50 GB in 2,995,971 files (average of 16 kB/file)
>   * Fibre channel 1 Gbps interface.
>
> General consensus was that we are being hit by the "many small
> files"
> problem, which certainly fits in with our situation.
>
> Things we've tried to date:
>
>   * Increased the DNLC and inode cache (see
>
> http://www.princeton.edu/~unix/Solaris/troubleshoot/kerntune.html
> --
>     very useful web page)
>
>     Slight improvement from this, but Networker is still timing
> out.
>
>   * Running uasm over the whole filesystem, piped to /dev/null to
>     eliminate the network as a bottleneck -- I aborted this after
>     eight hours (considering that we're "only" using 60 GB of space
> at
>     peak, and less than 50 GB after the processes using the disk
> clean
>     up after themselves, eight hours _should_ be adequate.)
>
>   * Removing the temporary working area from the backup -- again,
> maybe
>     a slight improvement, but it doesn't resolve the underlying
> issue.
>
> Executive summary: we've managed to get slight improvements, but
> Networker
> still likes to time out whilst backing up this filesystem. Sigh.
> Too many
> small files.
>
> At the moment, we're preparing to evaluate Sun's QFS as a possible
> alternative to UFS for this particular situation. Does anybody have
> any
> knowledge of how Networker interacts with QFS? Sun's representative
> is
> saying that our situation seems ideal for QFS, but then, I'd be
> inclined
> to take his words with a grain of salt :-) The biggest problem from
> my
> point of view is that Legato's compatibility matrix only lists UFS
> and
> VxFS; VxFS is an option, but it would be nice (if only from a
> bargaining
> point of view ;-) to have QFS as an option as well.
>
> As an aside, I'll be going on leave at the end of this week for a
> six
> week holiday, so the testing will be somewhat abbreviated (we have
> a
> thirty day evaluation license) ... I'll be picking up the ball once
> I get
> back, in late October.
>
> Ta muchly,
>
> Stuart.
>
> --
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