[Info-vax] SFTP hang - from VMS to Windows

[Jan-Erik Soderholm]

GerMarsh wrote 2013-02-25 16:19:
> On Monday, 25 February 2013 12:13:33 UTC, GerMarsh  wrote:
>> Anyone seen anything like this?
>>
>>
>>
>> We get intermittent hangs during file transfers - nothing consistent
>> about which file will be affected nor their sizes.
>>
>>
>>
>> Windows is running an OpenText (Hummingird) server. VMS is TCPIP
>> Services V5.6 - ECO 2.
>>
>>
>>
>> The "hang" can be kicked into life by trying an FTP connection to the
>> same server!
>>
>>
>>
>> The logfile shows something like this:
>>
>> sftp> ascii
>>
>>
>>
>> sftp> lcd /$1$DGA22/DATA/USERS/PC_SCHEDULE
>>
>>
>>
>> /$1$DGA22/data/users/pc_schedule
>>
>> sftp> cd /er_pc_root
>>
>>
>>
>> /ER_PC_Root
>>
>> sftp> put PC_ASCII_FILE.DAT
>>
>>
>>
>> PC_ASCII_FILE.DAT     |   96kB |  96.0 kB/s | ETA: 00:00:23 |   4%
>>
>> PC_ASCII_FILE.DAT     |  288kB | 144.0 kB/s | ETA: 00:00:14 |  12%
>>
>> PC_ASCII_FILE.DAT     |  384kB | 128.0 kB/s | ETA: 00:00:15 |  16%
>>
>> PC_ASCII_FILE.DAT     |  576kB | 144.0 kB/s | ETA: 00:00:12 |  24%
>>
>> PC_ASCII_FILE.DAT     |  704kB | 140.8 kB/s | ETA: 00:00:11 |  29%
>>
>> PC_ASCII_FILE.DAT     |  864kB | 144.0 kB/s | ETA: 00:00:10 |  36%
>>
>> PC_ASCII_FILE.DAT     |  1.1MB | 155.4 kB/s | ETA: 00:00:08 |  45%
>>
>> PC_ASCII_FILE.DAT     |  1.3MB | 168.0 kB/s | ETA: 00:00:06 |  56%
>>
>> PC_ASCII_FILE.DAT     |  1.5MB | 174.2 kB/s | ETA: 00:00:04 |  65%
>>
>> PC_ASCII_FILE.DAT     |  1.8MB | 185.6 kB/s | ETA: 00:00:02 |  77%
>>
>> PC_ASCII_FILE.DAT     |  2.1MB | 192.0 kB/s | ETA: 00:00:01 |  88%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 194.7 kB/s | ETA: 00:00:00 |  97%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 182.2 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 169.1 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 157.9 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 148.0 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 139.3 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 131.6 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 124.6 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 118.4 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 112.8 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 107.6 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB | 103.0 kB/s | ETA: 00:00:00 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB |  98.7 kB/s | ETA: 00:00:00 |  99%
>>
>> .
>>
>> .
>>
>> .
>>
>> PC_ASCII_FILE.DAT     |  2.3MB |   3.1 kB/s | ETA: 00:00:06 |  99%
>>
>> PC_ASCII_FILE.DAT     |  2.3MB |   3.1 kB/s | TOC: 00:12:46 | 100%
>>
>> sftp> quit
>>
>>
>>
>> The transfer sits at 99% with no throughput - and the associated
>> average rate decreasing.
>>
>>
>>
>> There is nothing significant in the logs on the Windows side but I
>> don't think the problem lies on the VMS end either.
>>
>>
>>
>> Networks support also state that there is no contention on the network
>> during these incidents.
>>
>>
>>
>> The process is not really hanging as it is dutifully outputting its
>> progress. Just sits in LEF state most of the time. Two BG devices in
>> use but I would expect that. No process or pooled quota issues
>> either.
>>
>>
>>
>> As ever, any pointers gratefully received!
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Gerald.
>
> Thank you for the comments and pointers. It is indeed an FTP connection
> which kicks the SFTP transfer back into life and the FTP is initiated
> from Windows.

*TO* what ?? The offenting Windows server?

Please spell out the full context, it's far to easy to
get lost between the boxes that are very wellknown to you. :-)

As I understand it :

A sftp session between host VMS1 (client) and Win1 (server)
hangs at the end at 99% complete.

A new FTP session from Win2 (client) and Win1 (server) get
the hanging sftp session to get "unlocked".

Yes, that does not look as it is the VMS box that is failing.

>
> I reckon that this fact indicates that this is not a VMS SFTP client
> issue at all.
>
> I discovered that the SFTP transfers worked consistently and much faster
> when the VMS and Windows boxes were in the same building. The Windows
> box has now been relocated a hundred miles or so!
>

The speed is mostly depending in the line speed, not the distance as such.
And is *should* not make the transfer to hang, normaly...

Jan-Erik.