As others noted, encryption/decryption is not cheap. But FTP is IO intensive over a very slow path, so transmission times ought not be impacted all that much.
I would suspect that network data compression facilities are being defeated. Because of the tiny block sizes used on many networks (less than 1.4 kbyte datagrams), even small increases in the number of bytes transmitted can have a rather heavy impact on transmission times. Encrypted data is not compressible. Another possibility is that network appliances are not reacting well to the encrypted data. If this is a z/os to z/os transfer, try MODE C TYPE E (in that order). That will compress the data prior to being encrypted. HTH. -----Original Message----- From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf Of Neal Eckhardt Sent: Thursday, September 24, 2009 2:19 PM To: IBM-MAIN@bama.ua.edu Subject: Slow FTPS thruput We are implementing FTPS, and noticed a breath-taking increase in the time it takes to transfer a file. A 20 megabyte file takes about 9 seconds to transfer without TLS and about 160 seconds with TLS. The transfer rates are about 130 kbytes/sec with TLS and almost 2000 Kbytes/sec without. Are there any tweaking knobs that we can turn to improve this? Thanks, Neal ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html NOTICE: This electronic mail message and any files transmitted with it are intended exclusively for the individual or entity to which it is addressed. The message, together with any attachment, may contain confidential and/or privileged information. Any unauthorized review, use, printing, saving, copying, disclosure or distribution is strictly prohibited. If you have received this message in error, please immediately advise the sender by reply email and delete all copies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
