iSeries SNA over TCP IP AnyNet support

Hi! I have 2 iSeries(os 6.1) in different data centers .  Speed of file transfer is about 200 mbit per sec. through 1000Gb adapter when I send 1 file by 1 batch job (SBMJOB CMD(SAVRSTOBJ OBJ(SAVFILE) LIB(SAVLIB) RMTLOCNAME(SYSTEM1)) ). The transfer speed grows to 800 mbit per sec. when I send 5 files in the same time  by 5 batch jobs through 1000Gb adapter. Why speed so little in the firs case? May be SNA has any limitations speed for transfer 1 file?
RVicAsked:
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gheistCommented:
In the normal world socket buffers should be able to accomodate all packets in flight
300mbit is quite normal if you dont intentionally tune sockets for 10GbE in one connection
Actually you found the best solution yourself - transfer in parallel.
(I know anynet, i doubt SNA has socket buffers over 64k-1, and the maximum speed per connection you get is speed of light in SNA-s world)
Gary PattersonVP Technology / Senior Consultant Commented:
Probably a simple disk read speed or write speed limitation.  You can't transmit data faster than you can read it off disk.   On the receiving side, you can buffer data for a while, but eventually you may run out of memory and be limited by physical write speed.

Look at WRKDSKSTS on each system as you submit each job, you'll probably see increased disk activity on specific disk units as you add jobs.

gheist has already outlined the solution: parallelism.

One solution is to create several smaller save files instead of one large one, and transmit in parallel to improve overall transmit time.

Another is to find or develop a multithreaded transfer application.  Not as hard as it sounds.  May be able to use PASE (AIX) utilities to accomplish the goal.

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gheistCommented:
Some 20 basic disks can feed gigabit. Typical iSeries has more of them.

You can name splitting data set into pieces in modern posh name = MapReduce ;)
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Gary PattersonVP Technology / Senior Consultant Commented:
A single big SAVF isn't likely to be split up evenly over 20 disk units, and since it is a non-database object it will probably be paged in using a single process unless you create some custom code, or cache it in memory ahead of time.

This isn't a data set in the sense used in talking about MapReduce - it is an archive file.  MapReduce isn't going to be much help with raw transfer of a big archive.  Really just need a good parallel transfer mechanism, hopefully reading underlying data from RAID array(s) with plenty of disk arms.
gheistCommented:
You can try pure tcp ftp if it is about a file alone, maybe it is a bit faster than SNA (at least one indirection less in any case)
Shalom CarmelCTOCommented:
A custom script that does local SAVOBJ, transfers via FTP and runs a "quote rcmd rstobj" is likely to work faster than SNA. I actually had a generic script that does exactly this, let me check my archives and see if I can come up with something.

--Shalom
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