[rescue] backup software

N.Miller vraptor at promessage.com
Wed Aug 6 15:21:27 CDT 2003

On Wednesday, August 6, 2003, at 10:34 AM, William Enestvedt wrote:

> Charles Shannon Hendrix wrote:
>> For the most part, I wish to have a scalable backup system that leaves
>> the actual archives in a format than can be read without the backup
>> system.

The OMT ("Official Management Term") for this is "bare metal restore".
NetBackup, iirc, has something to do this with.

>    NetBackup uses (GNU?) tar to write the archives, and its "database" 
> is a
> vast directory of ASCII files with ctime time-stamps.  Sure, I cuss 
> the out a lot, but at least I can write my own (homely) shells scripts 
> to work with the stuff. (Tape with multiplexed backups is another 
> question entirely...)

And if you are using any kind of linear tape drive, you want a
multiplexed backup, else you are chewing the heads on the tape
drive to shreds.  If you don't feed enough of a stream to LTO/
DLT/AIT, the tape basically saws back and forth over the head
as it writes each "line" of the tape on each segment (block?)
of the tape.  Very ugly.

This also explains why it is important to have no other traffic
clogging up the bus (SCSI/FC) from the host to the tape, and to
have a nice, stable, fast network feeding the tape host data.

I would recommend Curtis Preston's O'Reilly book to anyone
who is interested in backups: _UNIX Backup and Recovery_.
Preston knows both Netbackup and Legato, Oracle backup/
recovery, and wrote the O'Reilly book on SAN & NAS as well.
I took a class from him at LISA, and attended the BOF's
he ran--he knows his stuff.

His info web site is at: <www.storagemountain.com>


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