SFTP is very unreliable

Help & Support
1

I have been using for a few days and it seems to be very unreliable.

Transfers are slow and seems to slow down even more with the time: for example transferring a 71Mb file starts at 400kb/sec then slows down over time.

After some time I even get a timeout.

Here is the log from DOpus FTP Log panel:

SSH: Receiving neo4j-db.tgz
Timeout on Command 1018.
SSH: Error while reading: did not receive a valid SFTP packet
Connection closed
Opening Connection devv6.onmap-visual.com:22
30965760 bytes received in 206.875 seconds (145.520 Kbytes/sec)

=> Here it stopped at 30Mb only, and I didn't even get an error.

I then attempted to resume the download:

--
Opening Connection devv6.onmap-visual.com:22
Server version: SSH-2.0-OpenSSH_6.7p1 Debian-5+deb8u3
Using SSH protocol version 2
We claim version: SSH-2.0-PuTTY_Directory_Opus
Server supports delayed compression; will try this later
Doing Diffie-Hellman group exchange
Doing Diffie-Hellman key exchange with hash SHA-256
Host key fingerprint is:
ssh-rsa 2048 3f:2b:6a:64:f8:0b:18:18:2f:18:25:b5:a6:22:37:1a
Initialised AES-256 SDCTR client->server encryption
Initialised HMAC-SHA-256 client->server MAC algorithm
Initialised AES-256 SDCTR server->client encryption
Initialised HMAC-SHA-256 server->client MAC algorithm
Reading private key file "C:\Users\Nicolas\Documents\keys\admin.ppk"
Offered public key
Offer of public key accepted
Sent public key signature
Access granted
Initiating key re-exchange (enabling delayed compression)
Opening session as main channel
Doing Diffie-Hellman group exchange
Doing Diffie-Hellman key exchange with hash SHA-256
Initialised AES-256 SDCTR client->server encryption
Initialised HMAC-SHA-256 client->server MAC algorithm
Initialised zlib (RFC1950) compression
Initialised AES-256 SDCTR server->client encryption
Initialised HMAC-SHA-256 server->client MAC algorithm
Initialised zlib (RFC1950) decompression
Opened main channel
Started a shell/command
SSH: CTS CONNECTED
SSH: Receiving neo4j-db.tgz, restarting at file position 30965760
SSH: Error while reading: did not receive a valid SFTP packet
Connection closed

And again got an error, but this time I correctly got the DOpus error dialog.

I know speed can depend on network, etc but doing the same transfer with FileZilla always works (not interruptions or slow downs) and is a lot faster.

Right now it's so slow/unreliable that I have to use FileZilla instead of DOpus :frowning:

I can send more information if needed.

2

Could firewall or antivirus be involved, and treating Opus differently to Filezilla?

Does it only affect large .tgz archives, for example?

e.g. If antivirus is blocking and rescanning the whole .tgz each time data is written to it, it could cause it to get progressively slower as the file grows and takes longer to scan each time.

3

Personally I do not use SFTP for now, but I bough that possibility. And I remember other people report that problem, so I find that thread: Slow SFTP upload speed

4

I don't think that thread is directly related. It's about upload being slow and download being OK. (Something we do need to look at as it does seem one is faster than the other for some reason.)

This thead is about download speed slowing down as the file grows.

5

Any progress on this issue ?

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