🚀 go-pugleaf

A while ago, someone posted some "quoted" times for backing up to various
devices.  These quotes had come from DEC.   The device in question was
"how fast is a TK70 drive?" (compared to other tape devices).
 
Well, I have an excellent "benchmark" test, the results of which
follow.
 
In short, I must first summarize WHAT i backed up, and what our system
configuration is:
 
Disk to be backed up:    RA81 contaning about 200,000 blocks of data
                         and over 15,000 files.  (it's my uucp disk......)

How it was backed up:    BACKUP/LOG/IMAGE DISKNAME TAPENAME:SAVESET/SAVE
	  	         Job was processed on a standard (prior=3) batch queue.

Devices backed up TO:    TA78 at 6250, and a TK70 drive.
			 (note:  TA78 is on a HSC50)

System Configuration:     VAX 6320, 64MB, VMS V5.1-1, about 90 interactive
	   		  users were on at the time.


here's the accounting summary of the TA78 tape backup:

  BRODIE       job terminated at 19-SEP-1989 13:53:01.93
  Accounting information:
  Buffered I/O count:        33573      Peak working set size:   769
  Direct I/O count:          63666      Peak page file size:    2703
  Page faults:                 633      Mounted volumes:           1
  Charged CPU time:     0 00:13:00.24   Elapsed time:     0 00:46:15.17


.... and then here's the TK70 drive.

  BRODIE       job terminated at 19-SEP-1989 12:59:05.11
  Accounting information:
  Buffered I/O count:        32876      Peak working set size:   804
  Direct I/O count:          62673      Peak page file size:    2703
  Page faults:                 614      Mounted volumes:           1
  Charged CPU time:     0 00:12:56.10   Elapsed time:     0 01:46:05.53


Working set, page faults, and CPU time are all very close, however,
ELAPSED time is a little worse than I expected.   The TA78 took 46 minutes,
the TK70 took an HOUR and 46 minutes.   whoa.
 
I don't want to analyze this further, I'll let you all take a gander at the
stats.     Now, I imagine if I were to do the same backup on ONE LARGE file,
that the elapsed time would be closer, but who knows?


	-kent
-- 
Kent C. Brodie	Systems Manager at Large - Medical College of WI
UUCP:		[look at the message header.   domain reorg in progress.]
Ma BELL:	+1 414 778-4056
"*DOOOOP*"   -The Skipper {Gilligan's Island}