SLOW access to NAS drive

Hi all
been on here for about an hour and I'm stunned already! :D

Found this place whilst trying to resolve a problem though, so asking for some help please :D

My basic setup is hanging off a Netgear DG834GT, which then connects to a Netgear FS608 (10/100 switch).
On this switch I have my old laptop running XP Media Centre, my spanking new desktop running Vista Ultimat x64 (fully SP1'd) and a Buffalo NAS DH500GL.
All sit within a foot or so of each other and connect via cat5e.

When writing to the NAS from XP, I'm getting write speeds of about 3.7Mb/s
When writing to the NAS from Vista, I'm getting about 40kbs (yes, 'k' not 'M')
I get a similar 40kbs if writing from Vista to a shared doc area on the XP laptop.

Copying from the NAS to Vista (and XP) I get 3.7Mbs

Internet speed if similar on both for download (about 8Mbs) although I haven't tried upload speeds.

I've tried the auto-tune tweaks as suggested by Shane, and turned off DFS replication as suggested by DMEX.
Also tried plugging both the Vista box and the NAS into the DG834 incase the switch was causing the problem.
None of those helped

NAS firmware is fully up to date, as is Netgear DG834, and obviously the FS608 has no firmware to upgrade anyway.

At the moment I'm stuck with copying a file onto USB on the Vista box, plugging the USB into the laptop and uploading to the NAS from there - which reminds me too much of sneakernet technology


Any suggestions would be very gratefully recieved!

DIRY said:

Hi all
been on here for about an hour and I'm stunned already! :D

Found this place whilst trying to resolve a problem though, so asking for some help please :D

My basic setup is hanging off a Netgear DG834GT, which then connects to a Netgear FS608 (10/100 switch).
On this switch I have my old laptop running XP Media Centre, my spanking new desktop running Vista Ultimat x64 (fully SP1'd) and a Buffalo NAS DH500GL.
All sit within a foot or so of each other and connect via cat5e.

When writing to the NAS from XP, I'm getting write speeds of about 3.7Mb/s
When writing to the NAS from Vista, I'm getting about 40kbs (yes, 'k' not 'M')
I get a similar 40kbs if writing from Vista to a shared doc area on the XP laptop.

Copying from the NAS to Vista (and XP) I get 3.7Mbs

Internet speed if similar on both for download (about 8Mbs) although I haven't tried upload speeds.

I've tried the auto-tune tweaks as suggested by Shane, and turned off DFS replication as suggested by DMEX.
Also tried plugging both the Vista box and the NAS into the DG834 incase the switch was causing the problem.
None of those helped

NAS firmware is fully up to date, as is Netgear DG834, and obviously the FS608 has no firmware to upgrade anyway.

At the moment I'm stuck with copying a file onto USB on the Vista box, plugging the USB into the laptop and uploading to the NAS from there - which reminds me too much of sneakernet technology


Any suggestions would be very gratefully recieved!

Click to expand...

Good problem write-up. Have some rep.

Since the Vista machine appears to have trouble writing to both the NAS and the XP box, the problem is presumably not specific to the SMB implementation on the NAS but is instead on the Vista machine itself.

If you boot the Vista box to [safe mode + net] and attempt to upload from there to both the XP MCE and the NAS, is that also 40KBps?

thank you! :D

I'll try now, and report back in a mo...

yep, same (slow) speed in Safe Mode

DIRY said:

yep, same (slow) speed in Safe Mode

Click to expand...

Alright. I'll assume you've already tried plugging the Vista box into a different switch port and swapping the cables around... that sort of thing... it would be difficult for a faulty cable to produce such a symptom anyway.

Are you running the latest NIC driver on the Vista box?

Do you know how to create a packet sniffer trace? It would be useful if you could create a (relatively small) trace of one of those 40kBps uploads, zip it up, and upload it here. It should be relatively obvious whether there's a network or transport-level problem, or whether the Vista box is just slow for its own internal reasons, in which case it's back to a-huntin' bad drivers and filters.

To generate a packet sniffer trace, www.wireshark.com, install (on Vista), run as admin, select your NIC as the capture interface, start a capture. Commence an upload of something fairly innocuous (don't upload a text file containing your banking details!). After ~30sec of slow transfer, stop the Wireshark capture, save, zip up, upload here.

cheers for that

I believe I've got the latest NIC drivers, but I'll double check that in a mo

enc is the winzipped winshark result - which does seem to contain a LOT of checksum errors...

IPS used are:
192.168.2.3 = Linkstation NAS
192.168.2.88 = Vista box
file copied from Vista to NAS was the winshark install, which I ran for 30secs or so before cancelling (Vista was predicting 20mins or so).

thank you again! :D

PS interestingly, the 'upload file to forum' also seemed to run at about 40kbs (according to my sidebar network meter), but this might be either a red herring, or another example of the traffix being slow on writes I guess

DIRY said:

cheers for that

I believe I've got the latest NIC drivers, but I'll double check that in a mo

enc is the winzipped winshark result - which does seem to contain a LOT of checksum errors...

IPS used are:
192.168.2.3 = Linkstation NAS
192.168.2.88 = Vista box
file copied from Vista to NAS was the winshark install, which I ran for 30secs or so before cancelling (Vista was predicting 20mins or so).

thank you again! :D

PS interestingly, the 'upload file to forum' also seemed to run at about 40kbs (according to my sidebar network meter), but this might be either a red herring, or another example of the traffix being slow on writes I guess

Click to expand...

Good job. Don't worry about the checksum errors. They're a cosmetic side-effect of the fact that you're capturing on the Vista machine itself. The Wireshark capture driver gets to see the outgoing packet before the NIC hardware has calculated the correct checksum. Hence, to Wireshark, every single outgoing TCP packet appears to have an invalid checksum, but all the incoming ones are fine. If you traced at the opposite end, the situation would be the inverse.

This is actually quite an interesting situation. I can see the "slow", but the apparent reason is a bit odd:



The main body of the SMB file transfer commences approx. 23 seconds into the trace and continues right up to the very end. In say the first 40sec of that period, about 1,600,000 bytes of payload went across for an effective throughput of just under 40KiBps. The graph is nice 'n' linear, which indicates that whatever is causing the "slow" permeates the entire transfer, as opposed to some type of on/off jerkiness.

Looking more closely at one of the typical 32KB writes...

No. Time Source Destination Protocol Info
1077 0.000067 192.168.2.88 192.168.2.3 NBSS [TCP Previous segment lost] NBSS Continuation Message
1085 0.110891 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448415914 Win=32767 Len=0
1092 0.079976 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448418834 Win=32767 Len=0
1120 0.079999 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448421754 Win=32767 Len=0
1125 0.076575 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448424674 Win=32767 Len=0
1131 0.064503 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448427594 Win=32767 Len=0
1136 0.075272 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448430514 Win=32767 Len=0
1138 0.064068 192.168.2.3 192.168.2.88 TCP 445 > 49508 [ACK] Seq=1550273082 Ack=1448433434 Win=32767 Len=0
1140 0.043436 192.168.2.3 192.168.2.88 SMB Write AndX Response, 32768 bytes

Frame 1077 is part of the 32KB SMB "Write", except it's the only part visible to Wireshark, and it's a mere 1460 bytes of payload. The rest of the write is certainly there on the wire (because the other side is not complaining), and yet Wireshark doesn't see it.

That is almost certainly caused by a filtering NDIS intermediate driver.

Even so, the direct cause of the slowness is not the mangled SMB write but the fact that every one of the ACKs takes somewhere on the order of 40, 60, or even a hundred milliseconds to show up. The machine is waiting for the entire 32KB write to be ACKnowledged (SMB1 works that way), but that is taking far too long -a few hundred milliseconds per 32KB. Add all those delays together and that's where the glacial throughput is coming from. Since it happens with two separate targets (XP and the NAS), I doubt that both of them are slow. Instead, there's a driver down low in Vista's network stack which is interfering.

What firewall are you running?

Do you have a crossover cable that you could use to test what happens when Vista is connected directly to say the XP box?

Wow!

Thank you :D

I don't have a crossover cable to hand, but I'll try and get hold of one tomorrow.
I've currently got Windows firewall turned off, running the firewall on the DG834, and x64 version of Avast (although turning that off too seems to make no difference either).

For completness, if I copy the file from the IDE drive it is on, to the SATA C: drive, I get about 20Mbs

going off line for a mo to try cat5 e direct from Vista to NAS...

direct link from Vista to Linkstation NAS still at 40kbs

H2SO4 said:

Are you running the latest NIC driver on the Vista box?

Click to expand...

Wohoo! :D

that was it :D

(apols for the schoolboy error )

After fighting with the Nvidia 'support' website, managed to find an updated version for the ethernet drivers (replacing the ones I had from 2007 - said it was a schoolboy error!), and now I'm getting write speeds to the NAS of a little over 10Mbs :D

HUGE thanks for all your help on this, VERY much appreciated :D

DIRY said:

H2SO4 said:

Are you running the latest NIC driver on the Vista box?

Click to expand...

Wohoo! :D

that was it :D

(apols for the schoolboy error )

After fighting with the Nvidia 'support' website, managed to find an updated version for the ethernet drivers (replacing the ones I had from 2007 - said it was a schoolboy error!), and now I'm getting write speeds to the NAS of a little over 10Mbs :D

HUGE thanks for all your help on this, VERY much appreciated :D

Click to expand...

Glad to hear it's working well now. Based on that Wireshark trace, it just HAD to be one of the few drivers down low (at the "NDIS Intermediate" level), and the NIC miniport and 3rd-party firewall drivers are the most obvious examples.