I think you should be surprised. Or rather, deeply sceptical. I would certainly be very surprised to learn that an FTP implementation cannot handle files bigger than available memory. I have not done so in this thread, of course, because OP has named neither the distro nor any of the "various different" FTP daemons that allegedly have the issue. The description of the problem, "pi seems to fail", is also so vague as to neither support nor contradict the diagnosis.Joe Schmoe wrote:I never knew that (i.e., never experienced it) about FTP, but I guess I'm not entirely surprised.
The question I have it what makes you think it is not.CCitizenTO wrote:The question I have is why isnt the ftp storing only a certain amount of data before writing to the disk.
You seem to know a lot about how FTP programs behave. (I would not have expected them to fallocate, nor to write to a temporary file and rename.) But your theory that they behave differently on flash media is preposterous. Anyway, I have tested uploading a 3.6GiB file to a (SD card on a) Pi, and experienced no problems:I would imagine it has to do with flash memory being used because on conventional disks most FTP programs seem to reserve a section of disk space (like a block for the whoe thing) then write to a .part file or something like that at least while downloading.
Code: Select all
230 User pi logged in. Remote system type is UNIX. Using binary mode to transfer files. ftp> put distro.img local: distro.img remote: distro.img 227 Entering Passive Mode (192,168,30,30,181,27) 150 Opening BINARY mode data connection for 'distro.img'. 226 Transfer complete. 3892314112 bytes sent in 634 secs (6141.16 Kbytes/sec) ftp>
I appreciate that you only questioned whether the issue might be due to storing the entire upload in ram. But a couple of other participants have assumed that to be the case and then gone on to question the sense of it. Effectively insulting the intelligence of the program authors. I do not think it is harsh to point out that the diagnosis was unproven, and indeed wrong.scape wrote:The Pi is running Debian Squeeze and tried both vsftp and proftpd and on the client I tried both a custom python approach using the ftp module as well as filezilla ftp client, on two different computers running windows 7/64. I think if you reread my posts correctly, you'll see that I never pinpointed the reason nor did I forget to mention the OS the Pi was running on. Talk about some harsh forum users!
Code: Select all
(vsftpd) 227 Entering Passive Mode (192,168,30,30,87,206). 150 Ok to send data. 226 Transfer complete. 495892225 bytes sent in 171 secs (2897.76 Kbytes/sec) (proftpd) 227 Entering Passive Mode (192,168,30,30,212,26). 150 Opening BINARY mode data connection for usd.img 226 Transfer complete 1083999823 bytes sent in 359 secs (3022.69 Kbytes/sec)
Users browsing this forum: No registered users and 8 guests