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Welcome to the NFS package of the Network Hotline!
This package consists of the following:
* sales brief on HP's NFS product line . . . . . . . . . 11/12/91
* positioning statement: NFS -vs- Netware -vs- LM/X . . 11/12/91
-vs- Ftp -vs- DCE/DFS
* questions and answers about NFS . . . . . . . . . . . . 12/31/91
* NFS 4.1 Statement of Intent . . . . . . . . . . . . . . 12/09/91
* NFS Customer Slide Set . . . . . . . . . . . . . . . . 01/03/92
Best Regards,
Information Networks Division
Product Sales Brief Network File System {NFS}
I. EXECUTIVE SUMMARY:
NFS, the Network File System, developed by Sun Microsystems, permits
individual systems to transparently access and share remote files in a
heterogeneous network of machines and operating systems. NFS runs over
a local area network. NFS allows a variety of machines to act as
clients and servers both accessing and providing resources over the
network.
NFS ensures that files anywhere on a network appear local to user's
machines.
NFS has become industry's defacto standard for file access over a
network. According to IDC incorporated, by the end of 1990, there was
an estimated 2.2 million NFS nodes installed worldwide.
Over 300 vendors have licensed NFS and HP has NFS solutions for all
operating systems; HP/UX, Domain, OSF {future}, MPE/XL {third party},
and PC-DOS {third party}.
II. PRODUCT DESCRIPTION:
NFS, the Network File System, provides transparent access to remote
file systems on the network. NFS is a network service for data access
and sharing and provides a remote file access protocol. NFS enables
users and programs to access the data on remote machines as if this
data were local, thus providing the network transparency.
NFS is independent of the host operating system and therefore provides
data sharing amongst heterogeneous systems.
NFS uses the concept of Client and Server. NFS is actually one of the
first Client-Server distributed computing applications available to
market. A system running NFS can act as a client, server or both. The
Client makes requests to access data and files on Servers. Servers
make their specified resources available to clients. The two primary
concepts with NFS are MOUNTS and EXPORTS. For a client to access a
file system on a server, it must mount the respective file sysytem.
Servers must export all file systems that they want to make available
to Clients.
NFS is a stateless protocol. This means that NFS servers maintain no
client state info. Thus, if an NFS server crashes, no data is lost.
The client will continue to retry the operation. NFS operations are
also idempotent, meaning that any NFS operation can be executed many
times. It will always have the same meaning and effect. Statelessness
and idempotency provide for straightfoward crash recovery. When a
server is started back up, the client will retry the operation again
forever or until a configured timeout is reached. Statelessness also
means that unreliable transports, such as UDP, can be used and that
provides a significant performance advantage.
NFS runs over an RPC, Remote Procedure Call. This RPC is the ONC/RPC
as developed by Sun Microsystems. ONC stands for Open Network
Computing and is an umbrella term for Sun's distributed network
services running over the RPC. NFS is one of the distributed network
services within ONC.
NFS uses RPC at the "session" layer of the network. The RPC provides a
set of operating system independent operations for executing procedures
over the network, hence remote "procedure call". NFS uses the RPC and
in addition, application developers can write custom applications which
use the ONC/RPC.
NFS is one of the ONC network services; the service providing remote
file and resource access and sharing over the network. The other ONC
services can work with NFS and are as follows:
Network Information Service {NIS}: NIS was previously termed "Yellow
Pages". NIS provides a network-wide data management system. NIS
provides user-extensible databases for storing system information.
Information such as hostnames, network addresses, usernames and
networks can be stored in NIS. NIS in tandem with NFS can provide a
uniform view of the network to entire workgroups.
Lock Manager {LM}: The Lock Manager allows users to coordinate and
control access to information while using NFS. LM supports file and
record locking across the network. LM keeps the file system
coordinated and uncorrupted when multiple users are simultaneously
accessing files.
Remote Execution Service {REX}: REX is used to execute user commands
or programs over the network. REX can provide access to compute
capabilities not available on the local machine by extending the user's
ability to run programs remotely.
NETDisk: The NETDisk protocol allows a diskless workstation to boot
from servers that support the NETDisk protocol. HP does not support
NETDisk as we provide our diskless protocol called DUX for all HP/UX
systems.
Automounter: Automounter provides a dynamic facility for mounting and
unmounting remote file systems on an as-needed basis. With
automounter, clients mount server file systems on request by an
application or the automount command and mount points are automatically
removed after an expiration of a time value. Automounter coupled with
NIS can provide a dynamic, transparent view of the network to users
without painful system administration.
PC-NFS Daemon: The PC-NFS Daemon is a program that runs on an ONC-
based NFS server and provides authentication and print spooling
services to PC's running PC-NFS. HP's NFS products provide the PC-NFS
Daemon so that PC's can be integrated into networks with HP NFS
servers.
With the ONC/RPC is an additional "presentation" layer service called
External Data Representation, or XDR. XDR provides an architecture-
independent method of representing data. XDR shields hardware-specific
nuances for data types from the application programmer. Applications
using XDR may exchange data across heterogeneous hardware systems.
Our HP NFS Product line on all platforms includes all or a subset of
the above described ONC Network Services. HP/UX NFS includes all the
above services and MPE/XL, Domain, OSF and PC-DOS can and will contain
a subset of the above services. This information is detailed in the
section labeled "NFS Product Line Detail".
III. FEATURES AND BENEFITS:
FEATURES BENEFITS
******** ********
File/Resource Sharing Allows workgroup computing/workgroups can
with NFS share common files and resources for
better productivity
Storage savings incurred as files are not
duplicated on disks throughout network
Lower incremental costs to add
workstations as workstations will require
less storage resources and
software/applications can be shared off
the NFS server
Network-wide Admin with NIS Easier system administration by sharing
OS dependent files.
Network configuration changes can be done
at a "Master" server and propagated
throughout the network for FASTER
administration
Updates and Backups can be done centrally
Heterogenous Support Integration of multiple systems is
with NFS and ONC possible
Current investment is protected as NFS
and ONC runs on all major vendor
platforms including HP, DEC, SUN, IBM and
Apple
Industry Defacto Standard Allows for integration of multivendor
systems and PC's, applications and
peripherals on the network
On-going support and enhancements planned
from all major ONC vendors
Stateless Server Reduced overhead of tracking transactions
provides for good performance for NFS
servers
Client-Server Architecture Facilitates the evolution from terminal-
host timeshare environment to workgroup
computing using workstations and servers.
Allows for maximum use of MIPs on the
network
IV. VALUE PROPOSITION OF NFS:
The major Value Proposition of NFS, the Network File System, to our
customers is the increased PRODUCTIVITY by their knowledge workers and
design engineers that comes from sharing of workgroup data. The
ability to share and access remote data allows for no redundancy of
effort, no time delay for data transfer and automatic data and
information consistency amongst the team.
Decisions are made faster and product designs are implemented more
efficiently by the advantage of shared workgroup computing.
NFS becomes an enabler for this concept of shared workgroup computing
by providing the capability of remote file/resource access across a
network and file/data sharing. File and data sharing is accomplished
by using NFS to access the files and LockManager to keep the data
consistent.
ONC also provides our customers the RPC. This allows our leading-edge
application developers to begin developing and testing applications
based on the remote procedure call paradigm.
V. POSITIONING
1. Target Customer:
NFS, originated by Sun and licensed to over 300 vendors, started out as
the primary remote file access/file sharing mechanism for Unix
Workstation environments. It's use and administration is "unix like"
with access to NFS files done via the standard Unix file commands.
Unix users are comfortable in this environment and their use of NFS
becomes transparent.
The primary TARGET MARKET for NFS is small to medium Unix workstation
workgroups who have needs to share files, executables, resources and
graphics. For example, a target customer of NFS would be a group of
engineers designing Integrated Circuits using Cad/Cam software. They
would share product design tools via NFS on their Local Area Network.
NFS has also been developed for use over other system operating
systems. NFS for MPE, MVS and VMS exists. In addition, PC-NFS is also
available allowing a PC to act as an NFS client and access/share files
and resources on an NFS server.
Use and administration of NFS on the PC is done with DOS 3.1 commands
so for the PC user, they don't have to learn a new command syntax.
However, if the server is a Unix Server, administration of NFS is done
using unix commands.
The primary application market segments needing NFS are:
1. Case developers
2. ME/CAD design engineers working on product design
3. EE Engineers working on prototypes and IC design
4. Software development engineers
5. Documentation and desktop publishing developers
6. Complex financial applications using commercial Unix
Opportunistic markets are commercial markets needing access and sharing
of mainframe data as they begin mainframe downsizing and migrating part
of the mainframe application to the workstation.
2. Competition:
Since Sun Microsystems have made NFS source available for licensing,
many vendors have implemented NFS. Here is a summary of our major
competitor's product offerings and strategy:
SUN: Sun is moving agressively to have a viable NFS server product for
the marketplace. Besides being the industry leader in NFS, since they
originated the code, they are working towards performance enhancements
and have partnered with third parties to supply NFS write accelerators
and performance monitors.
Sun is currently on NFS version 4.1. They plan to have a new NFS
version 5.0 available sometime in late 1992. This version is being
designed to compete directly against DCE platforms. They plan to add
kerberos security and client file system caching into their NFS/ONC
product set. This additional functionality will compete against DFS
and kerberos in DCE.
The way to sell against SUN is in the areas of support, quality,
performance, and to get an understanding of the customer's application.
HP's overall NFS performance on our series 700's has been demonstrated
as better than SUN's using the benchmark NHFStones. Sun will try to
push NFS accelerators. However the accelerators only benefit those
applications which are heavily WRITE intensive. Most applications
using NFS are read-only such as sharing of source code libraries and
Man pages.
In addition, HP's quality hardware and networking means that their NFS
server will be more reliable and less prone to server panics. This
will insure more data integrity. In addition, HP has a long-term plan
to move fully into the area of distributed computing with DCE. Sun
does not plan to support DCE and are pushing ONC, which is not as
technically advanced as DCE.
DEC:
Ultrix: NFS 4.1 is available for Ultrix. In addition, DEC is
also adding value to NFS with the Legato Systems NFS write accelerator.
As with the SUN system, NFS write acceleration only becomes important
when applications are heavily write intensive. In addition, HP's NFS
can run in Asynchronous mode which will also improve NFS write
performance. See the question and answer section for more information
on NFS write acceleration.
VMS: DEC is providing NFS on VMS through a third-party,
Wollengong. Wollengong's product, called PathWay NFS Client for VMS 2.0
provides client functionality for the VMS system. The software
provides a VMS user interface to access files over NFS on other
systems. Wollengong can be contacted at 1-800-872-8649.
IBM:
RS-6000/AIX: IBM has NFS 4.1 for the RS-6000. In addition, they
have announced a "High-availability" NFS for the RS-6000 which
guarantees 99% integrity of NFS operations upon system shutdown. This
product will be available in 2nd quarter 1992. Position against the
RS-6000 with the quality of our systems and our NFS performance, which
exceeds that of IBM.
MVS: NFS is provided for the MVS mainframe through third-
parties. A Third-Party which offers NFS for MVS is BIM, Inc. out of
Belgium. They can be called in the U.S. at 1-213-653-9830 and at +32 2
759 59 25 for the non-U.S. locations.
OS/2: IBM is offering TCP/IP for OS/2 version 1.2 which includes
the NFS client capability.
3. Other technologies:
Other technologies can be considered competitors of NFS. Some of which
we develop here at HP. See the detailed positioning paper to follow
this section. Competing technologies can be considered:
AT&T's RFS:
This is a remote file sharing/access service available for UNIX systems
from AT&T. It is similar to NFS. AT&T was attempting to make it a
standard, however, the market went with NFS.
HP's RFA:
RFA is a remote file access protocol and is available for HP systems as
part of HP's Network Services, NS. It also runs over TCP/IP and LAN.
It is a proprietary remote file access solution. NFS has advantages
over RFA by being a defacto standard and as such, is available over a
wide range of vendor's operating systems and hardware. It also
provides file location transparency and central administration through
NIS, not available with RFA.
File Transfer Protocols; FTP, NFT and FTAM:
Any other method of getting a file from point "A" to point "B" can be
considered a competitor of NFS. HP has a myriad of file transfer
products including the three listed above. However, with file
transfer, you must maintain multiple copies of the file and you loose
the productivity enhancements that come with data and reosurce sharing.
PC-LAN File and Resource Sharing:
Lan Manager and Novell Netware both enable file and resource sharing on
the LAN. They can be considered competitor products to NFS. However,
they are better positioned for the PC-LAN environments where most
clients and servers are PC's. When you enter the realm of the Unix
Workstation workgroup, NFS supplies the best option for file and
resource sharing. See the detailed position paper to follow for more
detail in this area.
4. Emerging Technologies -- DCE:
DCE will have it's own Distributed File System, known as DFS. DFS will
be a super-set of NFS and will be available from HP on multiple
operating systems. HP is working on a clear and viable migration
strategy for our customers to migrate their NFS environments to DFS
environments in the future. We see DFS as the long-term technical
replacement for NFS. See the detailed position paper for more detail.
VI. NFS PRODUCT LINE DETAIL
HP Platforms:
{This information is also available in a slide format included at the
end of this document}
1. HP/UX Multi-user {8xx}
Today: Today our NFS product is based on NFS 3.2. It includes NFS and
the following components of ONC: NIS {YP}, Network Lock Manager, PC-
NFSd, {The PC-NFS daemon which provides support for PC-NFS clients},
REX, XDR, and the ONC/RPC.
Future: By mid-summer 1992, we will have included the following
functionalities of NFS 4.1:
Export of root
Exportfs {Directory exports}
Read-only exports
Automounter
2. HP/UX Workstations {7xx}
Today: Same as for series 8xx above
Future: Automounter will be going out for the series 700 systems with
system release 8.07 this January, 1992. In addition, by mid-summer,
1992, the series 7xx, 3xx, and 4xx workstations will have the following
functionalities of NFS 4.1:
Export of root
Exportfs {Directory Exports}
Read-Only Exports
Automounter
-noac {disable attribute file caching}
For more detail on future enhancements, reference the NFS 4.1 Statement
of Intent included at the end of this document.
3. PC MS-DOS:
For the PC, we reference the PC-NFS product. PC-NFS is available from
SunSoft Inc. or from FTP Software. To contact FTP software, call 1-
617-246-0900.
To contact your local sales office for SunSoft, call (800) USA-4-SUN
4. MPE/XL:
NFS on MPE/XL will be available from a third party. An NFS Server
implementation based on NFS 3.2 will be available from Quest Inc. in
January, 1992.
To contact Quest Inc., call 1-714-720-1434 in the U.S., and +44 0905
794646 in Europe.
5. DOMAIN:
NFS is available on Domain. With Domain system release 10.4, the
following NFS enhancements have been added:
XDR, the ONC/RPC, NIS, Lock Manager, PC-NFS support with PC-NFSd,
Automounter, REX and RPCGen. This will bring Domain up to parity with
HP/UX.
For more info on Domain, contact the America's Sales Center in Fort
Collins, Colorado at 1-226-2600.
6. Ordering Information
HP/UX:
NFS is provided with the HP/UX operating system for all series 800's,
700's, 300's and 400's.
The current HP/UX 8.0 operating system product number is B2438A.
MPE/XL: Order the MPE/XL NFS Server from Quest Software Inc. It is to
be available as of January, 1992. To contact Quest, call Quest
Software, Inc.
US: 714-720-1434
Europe: +44 0905 794646
PC NFS
Order PC NFS from SunSoft or FTP software.
*If you need testing of HP's NFS with
PC NFS 3.5, please contact the America's Sales Center, Cupertino at
1-447-4444. The Sales Center will then contact the Information
Networks Division with your request. IND will assess the resources
required and plan for the testing request. IND has tested NFS with PC
NFS 3.0 and earlier.
7. Sales Configuration
HP/UX:
For HP/UX, NFS will run over LAN or FDDI. LAN comes bundled with the
HP/UX product.
NFS has been supported since HP/UX 6.0 for the 300's and 2.0 for the
800's.
MPE:
For the MPE/XL NFS Server, you must have MPE/XL 3.0 or greater and an
HP LAN link product.
8. Sales Tools
In addition to this NFS Hotline, you can access:
1. Series 700 Performance Brief from WSY System Performance Team.
You can contact the team at 1-303-229-3890.
****Please note that this information is HP CONFIDENTIAL until the
Series 700 release 8.07 is announced.
2. HP AdvanceNet Specification Guide, part number 5091-1303E.
3. Customer Slide Presentation following this document
_______________________________________________________________________
Part 2
POSITIONING: NFS AND OTHER HP TECHNOLOGIES
A WHITE PAPER
NFS AND PC SERVICES; LM/X AND NETWARE
POSITIONING:
In positioning NFS and PC-NFS with Lan Manager and Netware, the primary
consideration is demographic. If the workgroup consists primarily of
Unix workstation users and they desire to integrate a PC or set of PC's
into their workstation environment, the easiest way to do this is with
PC-NFS. They would have NFS already functional on the workstations and
servers and they just need to load NFS on the PC's.
However, if the environment is a PC-LAN, most likely the customer is
already using a PC-Lan network operating system, e.g. Netware. In this
case, it would make no sense to introduce a new protocol set to share
data and resources. The functionality between NFS and Netware or Lan
Manager is almost identical, except for the fact that Netware and Lan
Manager have been tuned for the PC Lan environment.
NFS, on the other hand takes advantage of and has been tuned for the
Unix Workstation environment. One other consideration is that there is
NO NFS server capability for the PC, unlike Lan Manager and Netware.
In summarizing the positioning;
*Chose NFS and PC-NFS for those environments dominated by Unix
workstations and technical Unix Workstation users wishing to share
files and resources
*Chose Lan Manager and/or Netware for those environments which are PC-
Lans who need to share resources and files off a collection of servers
which could include PC servers, Unix or MPE servers.
NFS AND FILE TRANSFER PROTOCOLS: FTP AND FTAM
In positioning NFS -vs- File Transfer protocols, the main consideration
is the way the data is processed.
If data is processed by a single user or application, then sent on to
another location for further processing sequentially, then a file
transfer or messaging solution makes the most sense. For example, If
data is collected from a factory floor workcell controller, then sent
onto a plant manager machine for processing into a report, you will
find a protocol such as FTAM, file transfer and access management,
being used for this data transfer.
Note that the data is never shared. Some processing is done on the
data at the workcell controller level, then it is merely transfered
upward to the plant manager machine on the network.
However, many users and applications require shared data. Take, for
instance, the situation of a group of software developers all working
on a particular software product. Each developer is responsible for a
few modules of the entire software product. However, they will need
continual access to the modules of the other engineers. They may need
to see what changes their peers have made to the code or look at a
master include file to see code variable declarations.
To implement this working environment, all modules would reside on a
server system and the engineers would use NFS to access their modules
and their peer's modules from their personal workstation.
If a group of users or applications need access to data over time and
this data is shared by other applications or users, then NFS provides
the capability to do this. Data sharing and remote data access off of
specific servers cannot be accomplished by file transfer. File tranfer
forces applications and users to maintain multiple copies of such data.
NFS AND DCE
The part of DCE which will provide the Distributed File System is
called DFS. DCE provides a super-set of the functionality provided by
NFS, and the ONC services are similar to the other services provided by
DCE. HP's long-term strategy is to eventually replace NFS and ONC
environments with DFS and DCE, and this will begin with the
introduction of our DCE and DFS products throughout 1992 and 1993.
Note that customers will migrate from NFS to DFS overtime. Some early
adopters will be anxious to migrate and reap the benefits from DFS's
ability to present a global file system environment, easier
administration and wide-area capabilities. However, other customers
will be skeptical over DFS's value added and will wait before migrating
from NFS. Some may never migrate until they are forced by product
obsolesence. Realistically, NFS will continue to be an important
product to our HP/UX, Domain and OSF/1 customers for the next 2-3
years.
NFS is a fairly mature product as software environments tend to become
mature in a relatively short period of time. NFS has been around since
1987 and has built up a relatively large installed base, {approximately
2.2 million nodes}.
NFS does have some significant deficiencies in comparison to DFS. NFS
does not provide the true location independence provided by DFS. The
user still has to explictly work with the administrator to make sure
the remote files they need are mounted in their local file system.
With DFS and DCE, the user can see one global file system and get
access to any file assuming they have the correct permissions. With
NFS, maintaining a consistent file system view is difficult since
different system administrators can mount files differently on their
respective machines.
However, with the advent of Automounter, the system administrator can
get closer to the DFS vision of one global file system. By setting up
master Automount maps of all network mount points, and then propagating
the Automount maps thorough the network using NIS, each system can have
the same filesystem view. This is not as "clean" as the DFS method,
but can be an acceptable workaround granted the network is not too
large.
NFS also does not have the tightly integrated security that DFS has and
this is a problem for NFS. NFS is known to have some security holes
that continue to plague it's implementation. DFS is tightly coupled
with Kerberos as part of DCE.
Finally, DFS provides three additional features not provided by NFS
which positions DFS as a viable solution in a wide-area or enterprise-
wide environment. DFS provides: client caching for better consistency
of data shared between multiple clients and better client performance,
replication of data around the network, and the ability to function
over a wide-area network.
Today, NFS only runs over UDP which limits its performance over large
LAN environments and NFS does not run over X.25.
On the "flip-side" NFS is the best solution for smaller, cost-concerned
workgroups looking for file and resource sharing. By running over UDP,
there is less overhead so that local performance is better. Also, by
not being tied to all the DCE components, it has a lower cost per seat.
NFS is bundled with the HP/UX operating system.
Given it's strenghts and weaknesses, NFS is best positioned when:
*Users and applications are in small to medium heterogenous
environments
*The Unix workstation is the primary desktop platform
*Low cost per seat is a primary concern
*File sharing and access is done over a LAN
DFS will have the most value in:
*Large workgroups sharing data across multiple LANS or a wide-area
*File sharing that needs to occur in a secure environment, such as
applications accessing data off a mainframe or large mini-computer
which stores sensitive information such as financial or personnel.
*Larger heterogenous environments consisting of workstations, mini's,
mainframes and even PC's
*When file sharing becomes heavy and administration resources are
minimal, reduced administration time and cost becomes a key success
factor
_______________________________________________________________________
Part 3
COMMONLY ASKED QUESTIONS AND ANSWERS FOR NFS
I. Overall NFS Questions:
1. Is NFS a standard?
NFS is an industry defacto standard for transparent file access.
Currently, approximately 290 computer and communication companies and
universities have adopted it. NFS is easy to port to different
hardware architectures and operating systems. To encourage the
adoption of NFS, Sun has placed to protocol specifications in the
public domain. They have also placed the code for XDR, external data
representation, and RPC, remote procedure call, protocols in the public
domain.
2. Given that Sun licenses NFS to vendors, what is the reference port?
Reference implementations for 4.3BSD and Unix System V versions of the
Unix operating system are available.
II. HP-Specific Market Questions:
1. How long has HP had an NFS product?
HP has had NFS on HP/UX since the HP/UX release 6.0 for the series
300's and HP/UX release 2.0 on the series 800's. It was introduced as
a product in 1987.
2. I've heard there is more than one version of NFS, please explain?
Sun Microsystems developed NFS and did to things: 1) They made the
specifications to NFS available to the public and 2) They set up a
license program for other vendors who wanted to license Sun source code
to create their own products. Today, over 300 vendors have licensed
Sun's code and many have products. HP's NFS product on HP-UX is based
on the Sun NFS version 3.2. In Mid-summer, 1992, we will upgrade our
NFS to include features from Sun version 4.1.
In addition, with the availability of the specifications, research
projects began in Universities to create their own NFS products. One
of these projects became a viable implementation and was picked up by
Berkeley for inclusion into BSD Unix. Some NFS products are based on
this version and the NFS included in OSF/1 is this version. It is
fully interoperable with Sun's version.
3. Will HP move to NFS 4.1?
HP is planning to implement the primary features of NFS 4.1:
NFS 4.1 from SUN contains the following: All of NFS 3.2, NFS diskless
{NetDisk}, Automounter, Root access across specific mount points,
Directory Exports, Read-only exports, and Secure RPC.
HP will provide: All of 3.2, Automounter, Root access across specific
mount points, Directory exports, and Read-only exports. This
functionality will be available in Mid-Summer 1992 for series 800's and
workstations.
More more detail on this and reasons why we decided not to do NetDisk &
Secure RPC, please refer to the NFS 4.1 Statement of Intent.
4. What is Automounter and will HP provide it?
Automounter is a program that automatically and transparently mounts
NFS file systems when an NFS request is made. When the mounted file
system is not used for 5 minutes, Automounter automatically unmounts
the system.
HP will provide automounter for the series 700 workstation this
January, 1992. It will be available with the NFS 4.1 features for the
series 800, 300 and 400 in Mid-Summer 1992.
5. What is HP's strategy with respect to NFS/ONC and DFS/DCE?
We realize that NFS is going to be around for a long time. All the
major UNIX vendors ship NFS essentially free, {bundled with their Unix
operating systems}, and NFS has a large installed base, currently
estimated by DataQuest at 2.2 million nodes. As such, HP's strategy is
one of competitive parity for NFS. We need to continue to meet current
needs of our Workstation and Multi-user Unix NFS users.
HP is not planning any major product enhancements past the introduction
of our NFS 4.1 features in 1992. However, we will continue to
aggressively work to improve our NFS performance on the series 700's
and 800's. Performance is one area where HP can provide leadership.
We are the leader in workstation system performance, and by continuing
to optimize NFS operations, we can continually improve and measure our
NFS performance. We are currently working with the Workstation
performance lab to measure our NFS performance and make improvements
for the next workstation release. IND is also working with GSY to see
if efforts can be funded to measure series 800 NFS performance,
although no funding has been committed yet.
HP's future leadership focus for Distributed File Systems will be with
DCE and DFS. HP will be working aggressively to provide a strong DFS
product as part of DCE. However, we will continue to make NFS a viable
solution and provide a coherent migration plan as well for NFS to DFS.
NFS will supply needed interoperability as customers migrate to DFS one
step at a time. NFS clients will be able to mount DFS servers, so
customers can begin to migrate their servers to DCE and still be
operable in their familiar NFS client environment.
6. What is RFS and do we support it?
RFS is AT&T's Unix product for file access on Unix systems across a
common network. It provides file sharing and access capabilities for
medium sized workgroups of between 4-250 users. It is similar in
functionality to NFS but is not a defacto standard and as such is not
available on the wide range of vendor operating systems that NFS runs
on. NFS runs on most major vendor operating systems including; SunOS,
VMS, MVS, PC MS-DOS and MPE.
HP does not support RFS. NFS is our current networked distributed file
system of choice and will eventually migrate to DFS.
7. Do we support PC-NFS?
We have certified and tested our NFS product with PC-NFS versions 1.0,
2.0, and 3.0. We have not yet tested with PC-NFS 3.5, however it
should work as we support the standard PC-NFS daemon on the server. If
you have a need for testing with PC-NFS 3.5, contact the Americas Sales
Center at 447-4444 and they will forward the request to IND.
HP does not have a PC-NFS product however, our NFS for HP/UX and Domain
will work with PC-NFS products. PC-NFS products are available from
SunSoft, Wollengong, FTP Software and IBM. In addition, a PC-NFS
software product is available for the Apple Macintosh via InterCon
Systems Corporation, Herndon, Virginia.
8. Does HP's NFS product support NetDisk?
No, we don't support NetDisk, which is SUN's diskless client protocol.
WE have our own version of diskless client protocol called DUX, and we
also plan to support the DCE Diskless protocol at our DCE product
release for HP/UX and OSF/1.
9. Will OSF/1 have NFS?
Yes, NFS will be available with the first release of OSF/1.
10. Will NFS be interoperable with DCE?
NFS will be interoperable with DCE through the NFS protocol exporter
functionality. What this means is that NFS clients will be able to
mount, {access and share}, files from a DCE DFS {Distributed File
System} server.
NFS servers will not be able to service DCE DFS clients.
III. NFS Product and Protocol Specific Questions:
1. How many mount points can you have to an NFS Server:
Theoretically, clients can establish infinite mount points to the
server. Server capacity and application performance will set the
limits. NFS does not establish a limit.
2. Automounter: what is the difference between direct and indirect
maps?
An Automounter Direct Map contains a mapping of directories to their
client mount point.
An Automounter Indirect Map specifies subdirectories to mount under a
particular directory. An indirect map uses a key name instead of
specifying exactly the server mount point. The key name then acts as a
pointer into a Master Map which provides the exact mount point.
Indirect maps can prevent duplicate file systems from being mounted.
3. What is the difference between an NFS soft mount and an NFS hard
mount?
When you use NFS Soft mounts and an NFS request is sent to an NFS
mounted system and no response arrives, an error is returned after a
timeout period has elapsed. With NFS Hard mounts, the request will be
retried until interrupted or successful. It will not timeout. File
systems that are mounted as read/write should use the hard mount
option.
4. Can a single system be both an NFS client and an NFS server?
Yes, when you purchase the NFS product, you receive both the NFS client
and NFS server code.
5. What is the difference between using NFS in synchronous mode and
asynchronous mode?
By default, all NFS server writes are done synchronously to avoid data
loss due to the statelessness of NFS. {synchronous mode} However, by
specifying -a option in the /etc/exports file for the server, you will
increase write performance significantly by causing all writes for a
given file system to be done asychronously.
In addition, by coupling NFS in asynch mode and a UPS, {uninterrupted
power supply}, you can virtually guarantee that you will not have data
loss, however you will have a significant improvement in NFS file write
performance. This asynchrounous mode coupled with a UPS can be
positioned as a good alternative to the NFS write accelerators, such as
the Legato Prestoserver accelerator card, and does not require you to
purchase an additional piece of hardware which would use a system card
slot as well.
In chosing to mount NFS file systems asynchronously via specifying the
-async option in the /etc/exports file, you do increase significantly
the speed of file writes. However, because of the slight possibility
for data loss, you should not use -async mode when:
-- Files are accessed by the O_SYNCIO flag {which is set by the
fnctl (2) and open (2) calls}
-- data is accessed which cannot be reconstructed (e.g., a file
system containing database files)
-- Files are synchronized with fsync(2)
-- Critical applications are running requiring ABSOLUTE data
integrity.
6. What transport service does NFS run over?
NFS runs over UDP/IP. By running over an unreliable transport, NFS
performance is improved. However, it does limit you to local-area
networking. A future enhancement being investigated is the ability to
run NFS over TCP. No availability dates are set yet. This hotline
will be updated if plans get solidified.
7. I've heard information about different NFS performance
measurements. What are the industry accepted NFS benchmarks?
Today, the industry accepted NFS benchmark is NHFStones 1.2.2. This
benchmark is used by most vendors and gives a good indication of NFS
performance through the calculating of NFS Operations Per Second.
Sun has posted NFS performance numbers using something called NHFStones
2.03. By wary of these results, as it can by like comparing apples to
oranges. NHFStones 2.03 is not an industry accepted version of the
benchmark and it is critical in order to make valid comparisons to
understand the configuration under which the benchmark was run.
Critical items that would change benchmark results are configuration
parameters such as; how many clients and client daemons, {biod's} were
running, how many Lans were configured, how many disks per server were
configured, and what the NFS operations mix looked like, such as
%reads, %writes, %lookups, etc.
A new benchmark is being given to Spec for consideration as a standard.
It is called LADDIS and is a good indicator of NFS Server performance.
It doesnot take into consideration the client side of the equation
however. Pre-LADDIS, an early release version, is available to NFS
vendors for technical evaluation. HP has a copy and has run some
preliminary tests, however, the tests are not ready for quotation
purposes or competitive analysis. When LADDIS gets accepted by Spec as
a standard for measuring NFS performance, HP will post performance
numbers.
8. Where can I get more NFS performance information:
Current Nhfsstones benchmark results will be published in the next
series 700 Performance Brief available approximately at the end of the
year {1991} by WSY. Contact the WSY System Performance Team at 1-303-
229-3820 for a copy.
9. Is NFS a Client-Server application?
Yes, NFS is actually one of the first client-server applications
available to market. NFS runs over the ONC/RPC, remote procedure call.
When an user or application accesses a file over NFS, the RPC is used
to formulate the request over the network and effect the file however
the user intended, such as with a read or write. Part of the
processing takes place on the client and part on the server.
10. Where can I get more training on NFS?
The NEN2-9000/2D course is available for Field Engineers through PrSD.
It is currently being updated to include Automounter. In addition, an
excellent reference is available called "Managing NFS and NIS". This
book is available in all computer literature retailers and is published
by O'Reilly & Associates Inc.
For information in programming with RPC's, an excellent reference
exists called, "The Art of Distributed Applications", Programming
techniques for Remote Procedure Calls, published by the Sun Technical
Reference Library and also available in Computer literature retailers.
11. I have other questions related to HP's NFS product, where can I
get answers?
Please contact the HP Americas Sales Center in Cupertino at 1-447-4444.
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