Midnight commander file transfer "fish: storing file"

Question

when I copy files using Midnight Commander fuction named shell link (I guess it is kind of ssh ) it takes sometimes very long.

More precisely, the copy time-bar is finished quite fast (20MB/s), but than I have to wait much longer time for some mysterious operation which write to terminal message like

fish: storing file 16456464/111545454

because this stupid operation takes ~5x longer time than the actual copy (transfer over network) It really annoys me, and discourage me from using this network transfer function.

What is this operation, and why is it necessary, and how can I get rid of it ? (my theory that it is kind of encryption/decryption or copy from/to temporary directory or buffer ... but I was unable to google answer)

I think it happens only when I copy from client to host. But sometimes it is harder to exchange client-host role, e.g. if the computers are not in the same room or if ssh server is not configured on one of them.

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NOTE 1 : I'm pretty sure it has nothing to do with physical speed of network, the speed (slowness) is the same if I'm connected by 1GBit cable.

NOTE 2 : I know that using SCP or SSH, rsync or other terminal-based tools I can probably avoid this problem, which is perhaps mc-specific. But I find much more convenient mc gui, where I see what file is where and don't have to type commands all the time.

Answer 1

That "stupid slow operation" is actual copying over network using https://en.wikipedia.org/wiki/Files_transferred_over_shell_protocol

What actually may be stupid (or not) is first (fast) part, which is probably mc making local copy in /tmp (which it would do if you for example copied from zip archive or such, but should skip otherwise)

Answer 2

Uploading using fish is for some reason actually slower than most sftp clients. Also scp seems to be the fastest option, but lacks some of the features sftp provides.