On Wed, Jun 07, 2006 at 09:06:40AM -0500, Ty Young wrote:
> Just so you don't feel alone, I have run into exactly the same problem.
> In my environment there are a number (> 5) of Windows machines with
> millions of files within about 75 directories, all under "E:\" which are
> supposedly business-critical.    I used to be able to make the excuse that
> the symptoms you're describing are simply inherent with Windows, i.e. tons
> of tiny binary files, but this isn't always the case any longer.
> 
> But truthfully you're not alone and I think the disk-based backup (to which
> you could stage off to tape) is probably what a lot of shops use to get
> past this issue.

That argument implies (to me) that the tape infrastructure is the
bottleneck.  I would imagine if you have a system with too many files,
and that file system crawling process is the slowdown, it's not going to
matter if it's being copied to disk or tape - performance should be
about the same.  

I spent a second looking to see if I have any good collected data on our
environment on backup speeds, and unfortunately all I have is anecdotal
observations.  Our main file servers (which are Win2k3 storage servers,)
have millions of small files over large directory structures, and backup
(relatively) quickly -- I don't have any complaints about their backup
speeds.  I credit that to quantity and speed of the disks in the SAN
that make up its LUNs.  I also backup research group systems with very
large file systems on single spindle DAS disks, and those are the ones
that perform terribly, taking hours to walk/check the file system.

However, revisiting my first paragraph, if your D2D storage is on better
disk than the source disk, I guess it's possible you'd get better
performance later when it copies to tape.  But that doesn't seem to
solve the first copy problem (unless I'm missing something - if so,
please clue me in.)

Dave

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