Well. I have figure this out, more or less, but haven't solved the problem.
This is a known problem. Digital Unix does not write to NFS as fast as
Solaris or some other OS's.
I have been told there are some high end companies out there which
specialize in just accelerating NFS writes on machines with OS's like
Digital Unix.
I can trace it down more or less why it is slow, lots of big streams of
numbers and some fancy Excel charts put it all visually in focus.
I did the following tests.(all at 100meg Full-Dup on their own private
100meg switch)
This is with NFS v3, udp and tcp didn't make big differnce.
Sun platform was Solaris 2.6 11/98
DEC Platform was Digital UNIX V4.0D (Rev. 878)
Hardware settings are very similar, same type of drives, Sun Ultra60, DEC
600au.
DEC NFS writes to DEC and Sun NFS servers.
Sun NFS writes to DEC and Sun NFS Servers.
DEC write to local disk
Sun write to local disk
DEC write to RAM.
Sun write to RAM.
Well guess what. Here's how the results grouped.
Fastest:
DEC write to RAM, Sun write to Ram, and(surprise!) Sun NFS writes to DEC
NFS server, Sun writes to Sun NFS Servers.
Middle:
Both machines writes to local disk
Slowest:
DEC writes to NFS(not much slower though than the writes to local disk)
It seems that Sun does some really interesting cacheing of the NFS write
process.
I'm at the end of this problem. Not really solved, just understand it
more.Too many hours into this.
If you want to get a look at some of my results, excel charts,etc I can
email them to you. Just give me awhile to clean the charts up and make them
look more presentable,30+ hours, I am going to bed. Goodnight.
-grant
At 06:06 PM 2/9/99 -0800, Grant Schoep wrote:
>I have a problem with NFS writing on my DEC machines. We have a
>monitoring/logging process going that needs to write to an NFS drive, but
>for some reason, on our DEC machines, it goes too slow and can't keep up. I
>have tried numorous things. To many settings to even want to think about
>anymore. This same program runs on our Suns(Solaris 2.6) and runs by about
>a factor of 15 faster. One of our engineers broke it down and figured out
>that it was all slowing down on the writes to the drive. It wasn't the
>program itself.
>I have tracked it down to what am sure must be something with a DEC NFS
client.
>Here are the combinations I have tried.
>
>Sun NFS Server - DEC NFS Client = SLOW
>DEC NFS Server - DEC NFS Client = SLOW
>
>Sun NFS Server - Sun NFS Client = FAST
>DEC NFS Server - Sun NFS Client = FAST
>
>Sun Write to local drive = FAST
>DEC Write to Loac Drive = FAST
>
>The only factor that made it slow everytime was when it was a DEC NFS
>Client. The Sun wrote to the DEC NFS drive just as fast as Sun to Sun, but
>the DEC client still couldn't.
>
>I have tried the following changes on the DEC NFS client.These settings
>have been tried on a 400 mhz machine and a 600au machine. Both running on a
>lightly loaded 100meg network.
>
>Setting the NFS server and client deamons up 32/16, no change, besides,
>this is the only process running.
>
>Tried Hard/Soft mount options, no change.
>
>Tried setting the read cache and write cache up, no change, well, not
>better anyways, tried many settings, all powers of 2.
>
>Tried setting the inet settings:(Thanks to Mark Ray, who gave these to one
>of my engineers)
>udp_sendspace=655360
>udp_recvspace-655360
>tcp_sendspace=655360
>tcp_recvspace=655360
>tcp_mssdflt=655360
>Up by a good percentage, no help.
>(I also rasied the sb_max value to corrospond with these changes)
>
>I also tried setting the drive to mount as UDP and as TCP, no change.
>
>Turned sync on and off, (sync would take forever, or it just didn't work,
>didn't wait to see)
>
>Anything else I could try? Any ideas? I know these DEC have never realy
>been tweaked or optimally configured for our uses, maybe there is something
>I should do in general to help. I haven't done any patch installs on these
>machines either, could that be a problem? Is there a patch search database
>at DEC I could use to search their patches and see if there is a fix?
>
>Thanks for any help you can offer, hopefulyl I fan figure this out and put
>out a good SUMMARY on everything I did here.
> -grant
>
>---------------------------------------------------------------------------
>Grant Schoep, grant_at_storm.com
>System/Network Administrator
>L3 Communications Telemetry & Instrumentation
>San Jose,CA (408)271-0800, Ext. 135
>
---------------------------------------------------------------------------
Grant Schoep, grant_at_storm.com
System/Network Administrator
L3 Communications Telemetry & Instrumentation
San Jose,CA (408)271-0800, Ext. 135
Received on Thu Feb 11 1999 - 18:50:11 NZDT