ADSM-L

Re: Tape backup verification

2002-03-07 21:19:18
Subject: Re: Tape backup verification
From: William SO Ng <ngwso AT HK1.IBM DOT COM>
Date: Fri, 8 Mar 2002 10:15:19 +0800
I'm new to TSM, so please be patient with me.

Let say I backup directly from clients to tape, so my primary pool is tape
and I do not use a disk pool.

Since I cannot find "verify" command in TSM, so I wonder how TSM do the
verification ?  Is the data already been verified when it writes to tape ?
If yes, by whom e.g. tape driver, OS, TSM ?  If it is by tape driver or OS,
this mean that it is OS or tape driver dependent.  So some of the OS or
tape driver MAY NOT verify the writing process, so there is no guarentee
the data that backup is good ?

If the verification is done by TSM, then how does TSM do the verfication,
is it by checksum or read after write ?

Thanks,

Regards
William

Tivoli Software, IBM Software Group, IBM China/Hong Kong Limited
11/F, PCCW Tower, Taikoo Place, 979 King's Road, Hong Kong
Internet : ngwso AT hk1.ibm DOT com
Tel: 2825-7613                    Fax: 2825-0022





                    Bill Mansfield
                    <WMansfield@SOLUTIONTECHN       To:     ADSM-L AT VM.MARIST 
DOT EDU
                    OLOGY.COM>                      cc:
                    Sent by: "ADSM: Dist Stor       Subject:     Re: Tape 
backup verification
                    Manager"
                    <ADSM-L AT VM.MARIST DOT EDU>


                    03/08/02 07:29 AM
                    Please respond to "ADSM:
                    Dist Stor Manager"





When you backup the primary storage pool to the copy storage pool, it will
read the primary pool tape.  In the event the primary tape is bad, you'll
get a bunch of errors in the activity log.



_____________________________
William Mansfield
Senior Consultant
Solution Technology, Inc





William SO Ng <ngwso AT HK1.IBM DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
03/07/2002 03:14 AM
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Tape backup verification


Hello everyone,

I have some questions about backup verification and would like to seek
some
advice.

When I backup using TSM, how can I verify that the backup is good ?  What
I
mean is when TSM write to tape, how do I verify that the write-to-tape
process is good.  I come from VMS backup.  In VMS, it has a command:
BACKUP
/VERIFY, which will write the file to tape, rewind the tape and read the
backup file.  This will ensure that the file I wrote to the tape is good.
The disadvantage is backup time is much longer.   How does TSM do backup
verification ?  By checksum, by rewind and read ?  Is it possible to
specifiy the verification method ?

Regards
William

Tivoli Software, IBM Software Group, IBM China/Hong Kong Limited
11/F, PCCW Tower, Taikoo Place, 979 King's Road, Hong Kong
Internet : ngwso AT hk1.ibm DOT com
Tel: 2825-7613                    Fax: 2825-0022
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