topic Re: IO Count in Operating System - OpenVMS

IO Count

Denis Michaud — Fri, 17 Jun 2005 14:18:28 GMT

How can I get io count and bytes count after a backup operation on a tape device ?

Thanks

Re: IO Count

Garry Fruth — Fri, 17 Jun 2005 15:06:07 GMT

You can get the IO count to the tape drive by doing "SHOW DEVICE/FUL tape" both before and after and computing the difference. If you want to see how many IOs the process did, and assuming you are using the BACKUP command (as opposed to a software package that spawns a sub process), then use "SHOW PROC/ACC" both before and after the command. The IOs to disk may be a bit more difficult, in that disk IOs may be caused by other processes.

Re: IO Count

Robert Gezelter — Fri, 17 Jun 2005 15:11:06 GMT

Denis,

You can get the operation count for a device using the F$GETDVI lexical function.

The byte count is somewhat harder. You can get the byte counts for the process, but that will be a crude approximation whose accuracy will depend on the details of file size and other factors including fragmentation.

Possibly, you could do a BACKUP/LIST command and analyze the output (both the blocksize and the number of blocks are part of the output).

I hope that the above is helpful.

- Bob Gezelter, http://www.rlgsc.com

Re: IO Count

Willem Grooters — Fri, 17 Jun 2005 15:40:15 GMT

Try the follwoing qualifiers:
/LOG
/JOURNAL [=filename]

SPAWN of a procedure that runs BACKUP, consult ACC/FULL afterwards (limit output with /SINCE=time of start /BEFORE==end of job. /TYPE=SUBPROCESS /USER= you), the output of tyhe job will show info (including somewhat more). You _could_ force SET ACC/IMAGE before and SET ACC/NOIMAGE when done and look for BACKUP.EXE itself

SHOW PROCESS/FULL to get current state, run backup and do the same; calculate

These two are not exact, but the number of IO/s and bytes written by backup will be huge compared to the numbers extra for startup and initialisation.

(Running backup/journal at the moment, will tell results when finished)

Re: IO Count

comarow — Fri, 17 Jun 2005 16:33:52 GMT

If you submit the job, the accounting information will tell you the total number of direct and buffered IOs.

If you do it interactively, you will have to search for the accounting record, and it will give you that information.

Re: IO Count

Antoniov. — Sat, 18 Jun 2005 02:23:21 GMT

It's a bit hard.
Assuming intactive backup you can store your process counter
$ SH PROC /QUOTA/OUT=myQuotaBefore.log
you can make backup and then review quotas
$ SH PROC /QUOTA/OUT=myQuotaAfter.log
However, counters are either disk either tape worths.

Antonio Vigliotti

Re: IO Count

Denis Michaud — Mon, 26 Feb 2007 11:00:19 GMT

thanks