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From: seb022@tijc02.UUCP (Scott Bemis         )
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Ultrix disk transfer rates with UDA50s and RAxx disks
Message-ID: <157@tijc02.UUCP>
Date: Thu, 3-Sep-87 14:21:50 EDT
Article-I.D.: tijc02.157
Posted: Thu Sep  3 14:21:50 1987
Date-Received: Sat, 5-Sep-87 14:01:43 EDT
Organization: Texas Instr., Johnson City TN
Lines: 46
Xref: mnetor comp.unix.questions:3870 comp.unix.wizards:4071

What are the disk transfer rates in Kbytes per second with Ultrix 1.2 or 2.0 on VAX 8000 series computers?  I would really be interested in the disk transfer
rates with the Ultrix operating system on a VAX 8600 computer with UDA50 disk
controllers. Does the fast file system found in the Ultrix operating system 
really improve the amount of data transfered to/from the disk drives?

I am currently using a port of AT&T UNIX V Release 2.0 Version 2 on a VAX 8600,
with two UDA50 disk controllers.  Each UDA50 disk controller has it's own
Unibus. There are 1 RA60 disk drive and two RA81 disk drives on one UDA50
disk controller, and 1 RA60 disk drive and three RA81 disk drives on the
second UDA50 disk controller.  My disk transfers are very SLOW. For example,
the maximum transfer rate I have seen with the sar -d command is 40 Kbytes
per second.  The avwait time, the average in milliseconds that transfer 
requests wait idly on the queue, ranges up to 2000 milliseconds. Below is
the results of a sar -d command, to illustrate how I check the disk transfer 
rates.

	device - an odd way to refer to a RA60 or RA81 disk drive
	%busy - portion of time was busy servicing a transfer request
	avque - average number of requests outstanding during time 
		device was busy
	r+w/s - number of data transfers from or to device
	blks/s - number of 512 byte blocks
	avwait - mentioned above
        avserv - is the average time to be serviced (includes seek, rotational
		latency, and data transfer times for the disks). 
	
tijc02 tijc02 5.2 2 vax-8600    09/03/87

13:00:01  device   %busy   avque   r+w/s  blks/s  avwait  avserv

13:00:02   uda0        3     7.0       1       1   266.1    44.5
           uda1       11     3.8       3       6   111.4    40.5
           uda2       22    74.4       9      17  1883.6    25.7
           uda3        0     0.0       0       0       0       0
           uda4        5     2.9       2       3    63.1    33.1
           uda5        6     9.5       2       3   340.6    40.3
           uda6        1     3.9       0       1   111.6    38.4
           uda7        3     5.6       1       1   243.0    52.7

	   Any advice, comments would be appreciated.

	   Scott Bemis
	   Texas Instruments
	   Johnson City, TN
	   mcnc!rti!tijc02!root
	   Phone: (615) 461-2959