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FTPing Data from Keck
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(Good Morning!) Today is Friday, May 30, 2025. |
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It is possible to FTP data from Keck to an external site, although there are some
caveats to keep in mind. The first and foremost is that FTPing while you or someone
else is observing can slow down the network, disk access, cpu speeds, etc.
Keep this in mind, and have consideration for other observers. Also, keep an eye
out for speed problems, and if you see any while FTPing data, try stopping or
pausing the FTP process to see if that helps.
Generally you will want to FTP data from Keck instrument computers, where the raw data files are written, to some site over the Internet, either on Oahu or the mainland. in this case, as the data reside at the summit, and the external link to the Internet also is at the summit. If you are remote observing, for example, and you use start an FTP session from a headquarters computer, the image files will travel down the summit link to your computer, out the FTP link back to the summit to get to the external link, and then out to the receiving computer. Combining this with images coming down over the link to be displayed, and possibly to be read into analysis software being run or displayed at HQ, and you have a very stressed summit link. If you are at HQ, then, you can use "rlogin" to a summit computer, preferably a data reduction computer such as pelekane or hanalei. From there, "cd" to the relevant data directory, remembering that from these computers you need to prepend "/s" to the directory name, e.g. "/s/sdata101/hires3/...". Now when you FTP data it will go from the instrument computer (to which the /sdata disk is attached), to the data reduction computer, then straight out to the Internet, bypassing the critical HP-HQ link. |