seb022@tijc02.UUCP (Scott Bemis ) (09/03/87)
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) 461-2959gilgut@cg-atla.UUCP (Steve Gilgut) (09/04/87)
In article <157@tijc02.UUCP> seb022@tijc02.UUCP (Scott Bemis ) writes: >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, I would never put more than 2 raXXs on a UDA50, and I only put 3 ra81s on each of my kdb50s. The one exception is I have an ra60 on controller zero, and only because it gets used about twice a month. I have found the Unibus to be a bottleneck in my 11/785 and 11/750 experience. I do congratulate you on running two Unibus controllers. That's a big help. With the Unibus, you can only talk to one controller at a time, so at most, you can talk to two drives at once. Be a hero, and buy a VAX with the BI architecture. Now that I have an 8700 running Ultrix 2.0, with 5.5 Gig of disk, why, I'd rather fight than switch! Steve