Got it. With compression turned on, the 3590's were getting 28 MB/sec using FICON.
With compression turned on, the 3590's were getting 13 MB/sec using ESCON. Like Tom said, "You've gotta feed the beast". ____________________ Jim Hughes 603-271-5586 "It is fun to do the impossible." ==>-----Original Message----- ==>From: The IBM z/VM Operating System [mailto:[email protected]] On ==>Behalf Of Hughes, Jim ==>Sent: Monday, June 01, 2009 2:55 PM ==>To: [email protected] ==>Subject: Re: Z/VM and 3590 tape speed ==> ==>I am looking at table 3 on page 10 of the 3590 Introduction and Planning ==>Guide. ==> ==>It mentions two things of interest: ==>Device Data Rate(native) and Data Transfer Rate(maximum instantaneous). ==> ==>Device Data Rate for the E11 is 14 MB/Sec. ==>Data Transfer Rate depends on the channel. ==> ==>I guess what I am reading says the tape will move around at 14 meg/sec ==>no matter how fast I get the data to the device. FICON for tapes is a ==>waste of time. ==> ==>When would FICON for tapes be a good idea? ==> ==> ==>____________________ ==>Jim Hughes ==>603-271-5586 ==>"It is fun to do the impossible." ==> ==>==>-----Original Message----- ==>==>From: The IBM z/VM Operating System [mailto:[email protected]] ==>On ==>==>Behalf Of Tom Duerbusch ==>==>Sent: Monday, June 01, 2009 2:46 PM ==>==>To: [email protected] ==>==>Subject: Re: Z/VM and 3590 tape speed ==>==> ==>==>You're getting confused between tape drive speed and channel speed. ==>==> ==>==>The IBM 3590 E and H drives will read/write to the tape at a rate of ==>14 ==>==>MBs. Multiple that rate by your compression rate, if you have ==>==>compression turned on. ==>==> ==>==>The FICON channel, can operate at 200 MB or 270 MBs (on a z/890). ==>==> ==>==>So if you had 2:1 compression, you would see a transfer of 28 MBs. ==>==>Uncompressed it will be 14 MBs at best. ==>==> ==>==>And that is what you are seeing. ==>==> ==>==>These are data streaming drives. You have to feed the beast. If ==>your ==>==>source (disk) can't keep up with the tape drive and it's compression, ==>you ==>==>will see much, much lower transfer numbers. ==>==> ==>==>Tom Duerbusch ==>==>THD Consulting ==>==> ==>==>>>> "Hughes, Jim" <[email protected]> 6/1/2009 1:08 PM >>> ==>==>We have Z/VM 5.4, with 4 3590's attached to the z890 using FICON ==>Express ==>==>with the 2-Gbps feature. The tape controller is the A60. ==>==> ==>==> ==>==> ==>==>I am doing some tape speed tests and my results are not very good. I ==>==>have a pipeline(look below) that writes 65,500 byte blocks to the ==>3590. ==>==>I used the cms command TAPE MODESET ( NOCOMP/COMP to turn ==>compression ==>==>off/on. ==>==> ==>==> ==>==> ==>==>I see around 14 MB/sec with compression off and 28 MB/sec with ==>==>compression on. ==>==> ==>==> ==>==> ==>==>The 3590 Planning manual says the 3590's should operate at 200MB/sec ==>==>when using FICON with the 2-Gbps feature. ==>==> ==>==> ==>==> ==>==>There maybe a problem with my pipeline or my expectations. ==>==> ==>==> ==>==> ==>==>Here is the pipeline. Any insight or suggestions are welcome. ==>==> ==>==> ==>==> ==>==>/* */ ==>==> ==>==>arg blkcnt . ==>==> ==>==>if blkcnt = "" then exit 99 ==>==> ==>==> ==>==> ==>==>numeric digits 12 ==>==> ==>==> ==>==> ==>==>"TAPE REW" ==>==> ==>==>"TAPE FSF" ==>==> ==>==>say time() ==>==> ==>==>x = time("E") ==>==> ==>==> ==>==> ==>==>"PIPE literal <------------> | >> tapetest 3590 a" ==>==> ==>==> ==>==> ==>==>"PIPE (endchar ?) ", ==>==> ==>==> "? xrange 00-ff |", /* 256 characters*/ ==>==> ==>==> " dup 256 |", ==>==> ==>==> " specs todclock 1 1-* n |", ==>==> ==>==> " join 256 |", /* 64k */ ==>==> ==>==> " dup * |", ==>==> ==>==> " specs todclock 1 1-* n |", ==>==> ==>==> " fblock 65500 00 |", ==>==> ==>==> " take " blkcnt " |", ==>==> ==>==> " cnt: count lines |", ==>==> ==>==> " tape 181 |", ==>==> ==>==> " specs 1-1 1 |", ==>==> ==>==> " join 4999 |", ==>==> ==>==> " specs todclock 1 |", ==>==> ==>==> " dateconv 1.8 todabs ISODATE timeout |", ==>==> ==>==> " specs recno 1 ", ==>==> ==>==> " substring fs . f 1 of word 2 nw ", ==>==> ==>==> " /5,000 Blocks Interval Check/ nw |", ==>==> ==>==> " console |", ==>==> ==>==> " >> tapetest 3590 a ", ==>==> ==>==> "? cnt: | var xblkcnt | specs / Blocks written =/ 1 w 1 nw |", ==>==> ==>==> " console" ==>==> ==>==> ==>==> ==>==>____________________ ==>==> ==>==>Jim Hughes ==>==> ==>==>603-271-5586 ==>==> ==>==>"It is fun to do the impossible." ==>==> ==>==>
