SUMMARY: PCNFS seems very slow.

From: Bernard Bordonado (
Date: Wed Oct 12 1994 - 20:32:26 CDT

Hi, Sun Managers.

Many Thanks to all who replied.

I got 4 messages which was replied to my question - PCNFS is very slow.
In fact, this slowness is well known and some solutions exists.
(I didn't test any of them yet).

My original posting was as follows:

> Hello Sun Managers,
> We actually use a Microsoft Lan Manager Network with the following configuration :
> - An HP9000/800 server, HP-UX Version 9.04, with a fast and wide SCSI2 2Go Disk,
> and Lan Manager Version 1.4.
> - A Sun Sparc 10, who runs the PCNFS daemon.
> - About 30 PC under MSDOS/Windows with 3com ethernet cards (3c503 and 3c509),
> and the Lan Manager Client Version 2.1.
> For evaluation, we install a PC under client PCNFS Version 5.0 and we find it very slow,
> specially for saving and printing.
> So we measure the network transfer rate with Norton Sysinfo and obtain :
> READ 73.5 200
> WRITE 80.6 28.7
> (All values in Ko/second)
> These results are quite stranges.
> Does Norton Sysinfo is a valid tool for this kind of measure ?
> Is there an Unix tool to measure the PCNFS transfer rate on the server ?
> Is it a problem that the PCNFS daemon is not running on the machine who mounts the disk
> and the spool space ?
> Any kind of performance data, or network comparison will be wellcome.
> I will summarize.
> Thanks a lot.

----- Reply 1 -----

From: Pell Emanuelsson <>

NFS guarantees that a written block is really written to the disk before
the NFS request completes. I would assume that Lan Manager can buffer writes.
This can make a large difference.

I would also like to recommend you to check out the (PD?)
LanManager-compatible server "samba", which you can compile on your Sun
and thus dispose of PC-NFS completely. Samba is available by FTP, check
your nearest archie.

Cheers - Pell

Lysator Computer Society   |                  email:
Linkoping University       |    WWW home at:
Sweden                     |             or:

----- Reply 2 -----

From: Randy Olsson AWC <>

We have put a Prestoserver NFS Accelerator on our Suns to Speed up NFS writes. NFS reads are optimized, but NFS writes are slow without a Prestoserve. We noticed a 5-10 times increase in NFS performance. You can also tweak the read and write buffer sizes in PCNFS to change the performance.

----- Reply 3 -----

From: Andreas Holz <>


Yes, You are right!

PCNFS is very slow in writing to a UNIX Host!

We had this problem, when we wanted to use an Unix host as a database server for DOS-PC's. We found no solution (in 1992).

Meanwhile I found the following solution:

1) Use MS-Windows for Workgroups 2) use the TCP/IP 32 extension for WFW 3) use the XF32 package to mount Unix hosts via NFS, its is much more faster (~100Kb/s).

----- Reply 4 -----

From: Alan G. Arndt <aga@Comtech.COM>

In article <> you write: > LAN MANAGER PCNFS >READ 73.5 200 >WRITE 80.6 28.7

No suprise here. PC-NFS, like all NFS implementations, is Sychronous in it's writes. Meaning that the server should make sure the data is written to the disk (or stable media) before the write is acknowledged. The PC is in a much worse situation than the workstations because it only has a single thread for reading and writing. Thus you are extreemly limited in writes.

What I have done, and many others, is to either buy the prestoserve setup or for us cheapies, patch the server so that writes are no longer sync. This is, in some peoples mind, dangerous, in reality my server crashes about twice a year and the PC's twice a day so I am not to worried that the PC's will loose any data when/if the server ever crashes. I belive the HP's have a switch on in the mount specs to allow async writes. This would help there, but if the SS10 is the server you are stuck. I do have the patch for Sun OS 4.1.3, but not Solaris.

You should bitch to Sun, as I have, the PC Implementation should do two things. First, it should support multiple outstanding writes. That isn't to easy but others have done it. At least it is possible with Windows if not with DOS. Then they should implement the NFS V3.0 spec and allow the user to select if they want Sync or Async writes, as well as provide a utility or hook like smartdrv that will write all the data when you return to the dos prompt (or in windows after some time period, or completion of say a file save, etc).

The 200 K/sec reads is also pretty pitiful. In reality the PC could do well over 600K if PC-NFS were written better. That should be complained about as well. The more people that complain the more hope I have. They are limiting themselves to 1K reads to support old Network cards that can't handle back to back and/or 8K reception without the slow PC getting in the way. Well simply provide an option for those of us that have hardware to support that case.

In reality with 8K writes (which are possibly if your PC program explicitly writes 8K blocks) and a caching server you can, right now, get over 600K on writes with PC-NFS. I do. Unfortunately the Write cache on the PC needs to be extended to allow ALL programs to perform 8K writes. Not just those that are written to do so.

Hope that fills you in and helps solve your problems.

Oh, I use Norton Sysinfo as a quick test as well. It isn't perfect but it is relatively accurate for a simple quick test.

Alan Arndt Comtech Labs 415-813-4500 900 Hansen Way Palo Alto, CA 94304

----- Begin Included Message -----

Subject: Archie Search for Samba

Archie search for samba at

Host /pub/Linux/system/Network/daemons/.cap samba-1.7.07.tar.gz 0K (68 bytes) Sep 8 13:14 /pub/Linux/system/Network/daemons samba-1.7.07.tar.gz 198K (202965 bytes) Aug 28 00:44 samba.lsm 0K (987 bytes) Aug 28 00:45

Host /pub samba-1.7.07.tar.gz 198K (202965 bytes) Aug 24 16:40

Host /mount/archive.theory/answers/comp.archives/auto/comp.protocols.smb WFW-Samba-WFW-NFS-Solution-Found 2K (2062 bytes) Sep 5 07:21 /mount/common.lib.archive2/linux/sources/usr.bin samba-1.7.07.tar.gz 198K (202965 bytes) Aug 27 01:23 samba.lsm 0K (987 bytes) Aug 27 14:50

Host /.u1/Linux/Old/sources/usr.bin samba-1.7.07.tar.gz 123K (125952 bytes) Aug 11 08:33 samba.lsm 0K (985 bytes) Aug 11 08:33 /.u1/Linux/linux/slackware_source/contrib samba Aug 31 11:41

Host /pub samba-1.6.11.tar.gz 166K (170846 bytes) Jul 10 22:23

Host /os/linux/util/networking/netbios/alpha samba-1.7.09alpha2.tar.gz 202K (207281 bytes) Sep 6 14:01 samba-1.7.09alpha3.tar.gz 203K (207879 bytes) Sep 8 23:25 /os/linux/util/networking/netbios samba-1.7.07.tar.gz 198K (202965 bytes) Aug 4 08:01 samba-1.7.08.tar.gz 203K (208441 bytes) Sep 7 02:07 samba-latest.tar.gz 0K (19 bytes) Sep 3 01:40 samba.faq 15K (15776 bytes) Sep 2 10:11

Host /pub/uunet/usenet/control/linux linux.samba.announce.Z 2K (2080 bytes) Aug 29 10:40 ----- End Included Message -----

Thanks again to everyone.

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