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Old 10-19-2008, 06:21 AM
Craig White
 
Default Slow NFS writes

I guess I'm sort of surprised and I expected better performance

I have a new server set up with RAID 10 drives (6)

Repeated a number of times and though I am clumsy with stop watch
timing, these numbers appear to be close enough for government work...

Server, CentOS 5.2 and updated earlier today, just installed a week ago.

Client, Macintosh G4, OS X 10.4.11

NFS Mount is done with the following options...
-P (privileged ports)
intr
-r=32768
-w=32768
I tried doubling the size of the read/write windows to 65536 but it
seemed to make little difference.

Task, Read / Write 648 Megabyte Photoshop file (PSD)
Win2K = Win2K server (slow), RAID 5, Symantec EndPoint (ugh), retiring
this server
AFP = Netatalk from new CentOS Server
SMB = Samba from new CentOS Server
NFS = see above options, same CentOS Server

Copy To Win2K AFP SMB NFS
1m40.053s 0m22.566s 0m23.817s 2m11.849s

Copy From Win2K AFP SMB NFS
1m34.478s 0m20.709s 0m20.823s 0m23.487s

NFS read performance was slightly slower than AFP/SMB but the write
performance was poor.

I suppose that the answer is not so important because if the performance
was equal to AFP and/or SMB, they'd probably just use AFP anyway but I
did want to register my shock (or my ignorance).

Craig


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Old 10-20-2008, 05:21 PM
Joshua Baker-LePain
 
Default Slow NFS writes

On Sat, 18 Oct 2008 at 11:21pm, Craig White wrote


Server, CentOS 5.2 and updated earlier today, just installed a week ago.

Client, Macintosh G4, OS X 10.4.11

*snip*

Copy To Win2K AFP SMB NFS
1m40.053s 0m22.566s 0m23.817s 2m11.849s

Copy From Win2K AFP SMB NFS
1m34.478s 0m20.709s 0m20.823s 0m23.487s

Do you have any Linux clients to test with? That way you could determine
whether the problem is on the server or the client side. ISTR hearing bad
things about Apple's NFS implementation (shocking, I know). You also want
to test with larger files (at least 2x RAM of the server or client,
whichever is larger) to make sure you're not just seeing cache effects.


--
Joshua Baker-LePain
QB3 Shared Cluster Sysadmin
UCSF
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Old 10-20-2008, 05:49 PM
Craig White
 
Default Slow NFS writes

On Mon, 2008-10-20 at 13:21 -0400, Joshua Baker-LePain wrote:
> On Sat, 18 Oct 2008 at 11:21pm, Craig White wrote
>
> > Server, CentOS 5.2 and updated earlier today, just installed a week ago.
> >
> > Client, Macintosh G4, OS X 10.4.11
> *snip*
> > Copy To Win2K AFP SMB NFS
> > 1m40.053s 0m22.566s 0m23.817s 2m11.849s
> >
> > Copy From Win2K AFP SMB NFS
> > 1m34.478s 0m20.709s 0m20.823s 0m23.487s
> >
> Do you have any Linux clients to test with? That way you could determine
> whether the problem is on the server or the client side. ISTR hearing bad
> things about Apple's NFS implementation (shocking, I know). You also want
> to test with larger files (at least 2x RAM of the server or client,
> whichever is larger) to make sure you're not just seeing cache effects.
----
I was using a 648 Gb 'PSD' file which surely is beyond caching.

You definitely were correct in your assertion and stupid me should have
tested it from another Linux box.

$ time cp BackgroundGraphic.psd /home/filesystems/srv-adv/

real 0m18.547s
user 0m0.015s
sys 0m3.306s

so the problem isn't NFS slow writes...it's slow NFS writes from
Macintosh client ;-(

I'll play around a bit more but it's clear that no matter what I do, NFS
writes will never be faster than AFP or SMB from a Macintosh so given
the extra pain of setup, it's never going to happen.

Thanks

Craig

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Old 10-20-2008, 05:57 PM
Joshua Baker-LePain
 
Default Slow NFS writes

On Mon, 20 Oct 2008 at 10:49am, Craig White wrote


I was using a 648 Gb 'PSD' file which surely is beyond caching.


Your initial email stated "648 Megabyte Photoshop file (PSD)". Also,
your transfer times are on the order of 20 seconds. Unless you have a
network running at 32 GB/s, I don't think you mean 648 GB.


As an aside, it'd be fun to watch Photoshop try to open a file over half a
terabyte in size.



You definitely were correct in your assertion and stupid me should have
tested it from another Linux box.

$ time cp BackgroundGraphic.psd /home/filesystems/srv-adv/

real 0m18.547s
user 0m0.015s
sys 0m3.306s

so the problem isn't NFS slow writes...it's slow NFS writes from
Macintosh client ;-(


Get rid of the Macs. Problem solved.

--
Joshua Baker-LePain
QB3 Shared Cluster Sysadmin
UCSF
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Old 10-20-2008, 06:42 PM
Craig White
 
Default Slow NFS writes

On Mon, 2008-10-20 at 13:57 -0400, Joshua Baker-LePain wrote:
> On Mon, 20 Oct 2008 at 10:49am, Craig White wrote
>
> > I was using a 648 Gb 'PSD' file which surely is beyond caching.
>
> Your initial email stated "648 Megabyte Photoshop file (PSD)". Also,
> your transfer times are on the order of 20 seconds. Unless you have a
> network running at 32 GB/s, I don't think you mean 648 GB.
----
you're correct, brain not fully engaged yet. Transferring 549 GB did
take me around 18 hours or so.
----
>
> As an aside, it'd be fun to watch Photoshop try to open a file over half a
> terabyte in size.
----
I was playing around with that but what I felt was that I was testing
that particular Macintosh/Photoshop ability to VM rather than server
speed.
----
> > You definitely were correct in your assertion and stupid me should have
> > tested it from another Linux box.
> >
> > $ time cp BackgroundGraphic.psd /home/filesystems/srv-adv/
> >
> > real 0m18.547s
> > user 0m0.015s
> > sys 0m3.306s
> >
> > so the problem isn't NFS slow writes...it's slow NFS writes from
> > Macintosh client ;-(
>
> Get rid of the Macs. Problem solved.
----
Yeah but that isn't gonna happen...client is an Advertising Agency.

after adjusting settings some more, I got this when copying the file
from cli (using time command)...

0.005u 8.161s 0:19.49 41.8% 0+0k 0+20737io 0pf+0w

but you may be correct in terms of caching speeding things up. That
happened to be the largest PSD file I could find but I suppose I could
just create a dummy file and copy that to test. The 19.49 seconds speed
is much the same as I found using the AFP or SMB connections via the GUI
(Finder) allowing for the inaccuracy of my ability to start/stop the
time.

So I created a 1.5 gigabyte file using dd and copied that. What I did
figure out was that using the command line, copying the file took about
46 seconds via NFS mount but using the Finder to copy the same exact
file took almost 2 minutes longer to copy. There's obviously a lot of
latency in Macintosh Finder operations when 'writing' a file to an NFS
mount.

That same latency doesn't exist when using SMB or AFP mounts (copying
this same file using AFP took 37 seconds). I didn't find any caching
impact when copying any of these files and have found NFS usable, but
clearly a second class performer and thus, not worth considering.

For purposes of leaving a searchable footprint on the topic, this is
what I found to be the best NFS settings on the Macintosh client
(network is 1000BaseT)...

-P (secure/privileged port or otherwise you have to specify insecure on
NFS export)
-3 (to ensure NFS v3)
-T (to ensure TCP)
-intr (for softer landing if NFS server is unavailable)
-r=32768
-w=32768

Craig

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Old 10-21-2008, 08:24 AM
"A. Kirillov"
 
Default Slow NFS writes

> Client, Macintosh G4, OS X 10.4.11
>
> NFS Mount is done with the following options...
> -P (privileged ports)
> intr
> -r=32768
> -w=32768
> I tried doubling the size of the read/write windows to 65536 but it
> seemed to make little difference.
>
> Task, Read / Write 648 Megabyte Photoshop file (PSD)
> Win2K = Win2K server (slow), RAID 5, Symantec EndPoint (ugh), retiring
> this server
> AFP = Netatalk from new CentOS Server
> SMB = Samba from new CentOS Server
> NFS = see above options, same CentOS Server
>
> Copy To Win2K AFP SMB NFS
> 1m40.053s 0m22.566s 0m23.817s 2m11.849s
>
> Copy From Win2K AFP SMB NFS
> 1m34.478s 0m20.709s 0m20.823s 0m23.487s
>
> NFS read performance was slightly slower than AFP/SMB but the write
> performance was poor.

I had a similar problem with a freebsd box awhile ago
and the solution was to mount an nfs share with much lower
r/w buffer size (2048?). There also was something in the logs related to
nfs server timeouts or server not responding.

HTH


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