[Veritas-bu] NDMP Restores
2001-06-27 14:45:12
Hi,
Yesterday there was some discussion on these mailing
lists regarding NDMP and limitations on restores, etc.
We'd like to thank you for your feedback and to explain
what the current focus of NDMP is and in particular
how NetApp's chosen long term archivable backup format
(dump) works within NDMP.
Over the last few years NDMP has grown from
essentially a 2 company (PDC then IntelliGuard now
Legato and Network Appliance) backup solution to a
community with 20+ companies participating and > 25
NDMP compliant products shipping. The community
has backup software companies, tape library vendors
and file system vendors working together to achieve
true interoperability and a growing set of features.
This was the vision of the original companies.
Recently, this has resulted in a new V4 specification
that essentially is a cleanup of V2 & V3 and has
added extensibility so that new features may be
added without waiting for a spec change. V4
implementations will arrive this year from multiple
companies and should put an end to interoperability
issues that have cropped up from time to time.
NDMP (http://www.ndmp.org) is essentially a "plumbing"
api for controlling data protection/management operations
right now and has remained data format independant/neutral.
This means that it is relatively easy for backup software
companies to "plumb" a backup or restore that uses the
native format(s) of each system vendor.
There are 3 basic data formats commonly used in tape
backups, cpio, tar & dump (should we include MicroSoft
tape format?). Some operating systems such as Solaris
currently support all three. However, some systems such
as WAFL support one, i.e. BSD's dump. Even though systems
vendors have these native commands, most backup software
companies choose to write their own agents based on one
of the 3 formats discussed and tend to add some
"proprietaryness" as they support more and more dissimilar
file systems or add performance optimizations such as
multiplexing, etc.
NetApp's dump is no stranger to this, we have added support
for qtree metadata, NT ACLs, Unicode, NT Streams. However, a
standard BSD restore compatible application such as Solaris'
ufsrestore can still restore the data, but will only restore
NFS attributes. So should you have zero filers in 10 years
(heaven forbid) and a pile of NDMP/dump tapes to restore from
then as long as you have access to a dump compatible restore
program you should be able to manually retrieve your data.
Legato's BudTool product proved that NetApp data could be
restored on non-NetApp storage either in a disaster recovery
scenario or because that is what the customer wants. We'd like
to think that some if not all of the current 7 NDMP-compliant
backup software applications that support NetApp could add the
same capability.
Marion asks for a standard backup tape format that can be
interchanged between NDMP-compliant vendors and we applaud
her for it. However, that is beyond the current scope of the
NDMP community or the SNIA Backup working group in general.
We think its going to take an awful lot of persuading to get
all the current backup software vendors to define a single
format and then have all the possible system vendors support
it. Most companies have chosen their solution based on
trying to differentiate themselves from all the others and
we see that continuing for some time.
Cheers,
Grant and Greg
Greg Linn
Manager, NDMP Development
linn AT netapp DOT com
408.822.3752
=========== grant AT netapp DOT com ========== Grant Melvin
=== === Software Development Manager
=== === Data Availability & Management
=== |\ | __ ___ /\ __ __ === Network Appliance
=== | \ | |__ | /__\ |__| |__| === 475 East Java Drive
=== | \| |__ | / \ | | (R) === Sunnyvale
=== === California, 94089
=== === Tel:(408)822-6761
=========== Network Appliance ========== Fax:(408)822-4578
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