ASU support for CIFS Large writes (CAP_LARGE_WRITEX)

[Jeff Barnes_3]

We're running ASU on Tru64 5.1B and users are reporting slow file copies from native Windows servers to ASU Shares.

I've noticed that ASU (LM2.1) does not support CAP_LARGE_WRITEX. Is there any way to turn this on, and if so, where?

Also, does anyone else have other suggestions to improve the performance of file copies from Windows to ASU shares.

Thanks.

[Al Licause]

Can you be a bit more specific....when you say slow....how slow ?

How fast or how many bps would you expect of such a transfer and how many are you seeing ?

What are the network card interface speeds ?

Is either system experiencing any errors ?

Have you tried looking at the transfer with tcpdump or Ethereal yet ?

[Jeff Barnes_3]

>>Can you be a bit more specific....when you say slow....how slow ?
>>How fast or how many bps would you expect of such a transfer and how many are you seeing ?
This is the subjective part. My clients indicate that, all things being equal, copying files from Windows to ASU is 'slower' than copying files to other native windows servers.

>>What are the network card interface speeds ?
Clients are 100 Mbps/ASU server is 1000 Mbps. No errors indicated.
Is either system experiencing any errors ?

>>Have you tried looking at the transfer with tcpdump or Ethereal yet ?
Yes, that's how I found that, during SMB negotiation, large buffer writes are not supported.
ASU for VMS originally only transfered 4K buffers and could be tuned upward. I'm wondering if this is not a similar issue for ASU for Tru64.

My client also indicates reading is also slow, so I am less inclined to blame it on this only. We've checked permissions, access rights etc.

Thanks for your interest.

[Al Licause]

Unfortunately ASU is supported by a different group and I don't know if there are any ASU specific parameters to allow for larger buffer sizes.

I'll see if I can find an ASU resource to chime in here unless anyone else can post first.

Just out of curiosity, have you tried a simpler application like ftp just to see if you can raw throughput exchanges in both directions at the speeds that you would expect given the network speeds available to your systems ? The point being to make sure that the problem is ASU specific and not system tunning.

Also since one side is 1000Mbps and the other is 100Mbps, if you are exeriencing slowness from the server to the clients then check to see if your network switches support flow control on the 1000Mbps side. Try enabling it if is exists and is not enabled.

[Jeff Barnes_3]

This problem still remains.