Networker

[Networker] Windows, POSIX/NFS, filenames and backups

2005-09-22 11:53:23
Subject: [Networker] Windows, POSIX/NFS, filenames and backups
From: Dave Mussulman <mussulma AT CS.UIUC DOT EDU>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Thu, 22 Sep 2005 10:44:42 -0500
This summer, we transitioned our older Sun file servers to a SAN
front-ended by Windows 2003 NAS boxes.  We gained better file system
access control granularity by switching to CIFS, and have been using
Windows Services for UNIX (SFU) to provide NFS mounts of that data.
Service-wise, it's working fine, but we've run into a hitch backing
things up.

The problem relates to the POSIX subsystem/SFU/NFS server will write a
file to the NTFS file system in a way that it breaks the Windows file
API, so Explorer and ntbackup/Networker cannot view/open the file.  For
example, the POSIX side understands mixed-case filenames while Windows
does not (or at least doesn't differentiate between them.)  So, under
SFU/NFS you can create a file named "test" and a directory named "Test"
-- and it will create them and manage them as expected under NFS.  When
you browse them with Explorer, both files exist (a case that couldn't
happen if you created them both in Windows,) but you can't access one of
them.  I couldn't open the 'test' file, but I could go into the 'Test'
directory.  The same thing applies for files that end in a dot (latest
and latest. are different in POSIX but the same in NTFS.)

Networker complains about each of these cases when I do a full backup,
and doesn't actually backup all the files.  ntbackup fails too, so I'm
assuming this is a Windows bug not a Legato one.  We opened a case with
our vendor (HP,) who escalated it to Microsoft, but the preliminary
replies make me feel this isn't something they're going to fix.

I think it's pretty irresponsible that Microsoft will create a product
that will let you create files that you can't backup.  (Or, rather, that
the POSIX API that NFS uses has some level of access to the file system
that Explorer and the backups APIs don't have.)  I don't have a
solution, or a work around for this, except for a hope that Microsoft
will fix it (either as a patch or in Vista.)  If I understand things
right, they're going to roll Services for UNIX into the core Vista
Server - maybe then they'll have to acknowledge and fix this.  (This is
mainly an FYI for people using SFU.)

Dave

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