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| 2021-10-11 | 2021-10-11 | ||
| no summary (95.85.128.26) (hidden) (untrusted) | Restored revision 1611698842. Undoing revision 1633906267. (martin) (hidden) | ||
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| In case the speed is throttled by %%CPU%%, it may help if you choose different encryption algorithm on //[[ui_login_ssh#encryption_options|SSH page]]// of Advanced Site Settings dialog (supposing you are using SSH-based [[protocols|file transfer protocol]], such as SFTP or SCP). //Blowfish// is usually a lot faster than //AES//. It may also help, if you turn off [[ui_login_ssh#protocol_options|compression]], if you have turned it on before. | In case the speed is throttled by %%CPU%%, it may help if you choose different encryption algorithm on //[[ui_login_ssh#encryption_options|SSH page]]// of Advanced Site Settings dialog (supposing you are using SSH-based [[protocols|file transfer protocol]], such as SFTP or SCP). //Blowfish// is usually a lot faster than //AES//. It may also help, if you turn off [[ui_login_ssh#protocol_options|compression]], if you have turned it on before. | ||
| - | porn | + | ===== Network Delay/Latency ===== |
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| + | Network delay/latency affects particularly %%SFTP%%, as it is a packet oriented-protocol. When trandferring, the SFTP client (WinSCP) sends a read/write request to the SFTP server, waits for a response; and repeats, until the end of the file. | ||
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| + | Even if your connection is fast, if the server is far away (or slow), it takes a time for the response to arrive back. If the client spends this time uselessly waiting, your transfer speed will be low. | ||
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| + | Most SFTP clients (including WinSCP) overcome the problem by both requesting/sending a large chunk of the file in each single read/write request and by sending (queuing) multiple requests without waiting for a response to previous. For example WinSCP can request up to 32 chunks for 32 KB each at once, totaling 1 MB (these are defaults which can be altered with ''SFTPDownloadQueue'' and ''SFTPUploadQueue'' [[rawsettings|raw session settings]]). But if there's a big discrepancy between the bandwidth and the network delay, even that 1 MB can be too small to saturate the bandwidth. | ||
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| + | See also [[wp>Bandwidth-delay_product|Bandwidth-delay product]] on Wikipedia. | ||
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| + | In case the speed is throttled by a connection latency, it may help if you use [[scp|SCP protocol]] instead of [[sftp|SFTP]]. %%SCP%% is less affected by the latency. In this case, it may help if you turn on [[ui_login_ssh#protocol_options|compression]]. Toggling //[[ui_login_connection|Optimize connection buffer size]]//, in either way, can help too. | ||
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| + | An underlying TCP protocol can suffer a similar problem too. In which case it will affect all other protocols, including SCP, FTP, WebDAV or S3. | ||
| ===== Relation to PuTTY PSCP/PSFTP ===== | ===== Relation to PuTTY PSCP/PSFTP ===== | ||