Does make_tape_recovery rewind?

[Tim Jaster]

I want to set a cron job that performs make_tape_recovery daily...

00 18 * * * /opt/ignite/bin/make_tape_recovery -I -v -x inc_entire=vg00 -a /dev/rmt/0mn

I know I need to use a "no rewind" device, however, I wish to overwrite this tape with each day's backup. Does make_tape_recovery perform a rewind when it starts? Or do I need to perform a rewind beforehand?

Our previous administrator was using make_recovery with /dev/rmt/0m (rewind).

Also, will a recovery booting off of such a tape rewind when it starts?

Thanks

[Pete Randall]

Your previous administrator obviously never had to recover from one of those tapes - they were worthless.

If you want to overwrite, simply use a "mt rew" command before your make_tape_recovery command.


Pete

[Steven E. Protter]

Pete's answer which I agree with leads me to another STRONG recommendation.

You need to find a way to test this tape.

There is no other way to be sure it will work.

I was "fortuneate" enough to have to recover a D320 server soon after I learned how to use the make_recovery(now make_tape_recovery) command.

SEP

[Bernhard Mueller · Accepted solution]

Hi,

to answer your questions:
Does make_tape_recovery perform a rewind when it starts? YES

Or do I need to perform a rewind beforehand? NO, but it would not hurt issueing an mt -f /dev/rmt/#m rew

Also, will a recovery booting off of such a tape rewind when it starts? Not sure, but if you cycle power or take the tape out and put it in again, it will do a rewind.

Regards,
Bernhard

Regards,
Bernhard

[Bernhard Mueller]

As for your latest question again. I am pretty sure that a

bo

does not change the tape position in any way. But it is assumed that you "put it in when you need" (and then it will rewind), hence it is logical that make_tape_recovery does a rewind first.

If after running make_tape_recovery you do
mt -f /dev/rmt/#mn fsf 1
Ctrl-B (GSP login)
RS (Reset system)
any key to halt at BCH
bo

it may be possible that you cannot boot but have to take the tape out first.

Regards,
Bernhard

[Tim Jaster]

Thanks for all of your help. I have created a script to first do the rewind, then the make_tape_recovery. We'll see how it goes tonight.

BTW, we are planning on a full disaster recovery test very soon.

[Bill Hassell]

I would strongly suggest creating a script to do this Ignite task rather than just running the command. The reason is that cron doesn't have any logic to check the tape. You might have a write-protected tape in the computer and all will seem to be OK. You would have to read the current logfile every morning to see if all went well. Attached is one that I use which tests if the process went well and provides useful error messages (like no tape, write protected, fixes CDROMs in fstab, creates a local log file, etc)

[Charles Holland]

Bill,
Can't follow your script meaning in lines 82 and 131. Both are echo commands with
${IV} which comes up with "IV: Parameter not set." What is this supposed to equate to?

Thanks
Chuck Holland

[Bill Hassell]

Sorry about that. These are video enhancements ($IV = inverse video). You can remove the variable or assign it near the beginning of the script:

IV=$(tput bold)

Here are the other most useful enhancements:

export HB=$(tput dim) # dim text
export HV=$(tput smso) # 1/2 bright inverse
export IV=$(tput bold) # inverse
export UL=$(tput smul) # underline
export BL=$(tput blink) # blink
export EE=$(tput sgr0) # end all enhancements

To see these enhancements, use the enclosed script.

[Bill Hassell]

Oops, hit submit too soon...here is the script called ttyenchance.

[Jeroen Peereboom]

I wanted to add something although many good things have been said by the others.

Since you create recovery tapes, I assume you change tapes each (working) day. The tape will be rewound when inserted to the drive.

Having multiple 'backups' on 1 recovery tape seems not wise (cannot be used for recovery?), and overwriting the same tape daily also seems not wise. You need more than 1 tape for security reasons.

So I wondered why you asked your question (though it is correct that you use the norewind device now).

I don't understand your strategy of overwriting this backup daily.
I used to create a recovery tape twice a year, or more often depending on the patches and updates).

If you have more than 1 volumegroup your backup is not complete. (But you probabaly know that).

JP.

[Tim Jaster]

Jeroen,

Our make_tape_recovery does run every day (overwriting the previous day's backup), however, we only replace the tape every two weeks, sending the latest backup to off-site storage. Since we apply patches monthly, it's nice to have two sets of tapes for each month.

It is true that running the backup every day is not totally necessary, but we figured we would have the most up-to-date dynamic data in case a restore was possible with the tape currently in the drive. If the whole system was destroyed, we'd still be good enough with the biweekly off-site tapes.

Finally, we do run backups with Data Protector on the other volume groups.

-Tim