SUMMARY: Backups

From: Bill Murray (71213.2657@CompuServe.COM)
Date: Sat Mar 19 1994 - 21:15:07 CST

About a month ago I asked a question about backups. What's best to do for
backup of a SparcCenter 1000. I got about 25 replies. Thank you everyone for
your fantastic support.

All 25 replies had varrying answers. You probably know better than myself, on
Solaris 2.2, there are many ways to backups. UFSDUMPS, CPIO's TARS etc. The
real question is not really how do I do a backup but instead, when I do a backup
is it going to be any good when I need it? This is where your responses were
helpful. Some people said they did backups with the above methods when the
system was in use and never ran into a problem. Others insisted that I should
umount the file systems then do a fsck and then do my backup with ufsdump.
Those who insisted on this last method had some bad experiences and they felt
this was the only secure way for a backup. The Solaris manuals themselves
explicitly point out that if you have users on the system you run the risk of
having a backup that might not be able to be restored if you use one of the
above methods.

One user told me that after using CPIO with users on the system attempting to
restore failed because cpio didn't have a match between the file size in the
directory and the actual bytes in the file.

So then I was curious about BACKUP ONLINE, (for sell by SUN). Unfortunately SUN
can't tell you how the tape is verified or if it is verified. And SUN can only
backup files on the system if it locks whole filesystems before backing up. Or
their default is set to skip files that are open altogether or retry them. This
file locking on whole filesystems is really not pratical for someone who wants
to backup up online and has all their accounting files in one filesystem.

Then there's third party software for backups. I tried BRU from Enhanced
Software Technologies. It cost me $799.00. There address is 5016 S. Ash Ave,
Ste 109, Tempe AZ 85282-6845. Phone 602-820-0042 and Fax 602-491-0865. This
backup software is great. My throughput on our SparcCenter 1000 with a Archive
DAT drive is approximately 500-600kb per second. BRU not only verifies that the
information is written correctly to the drive but it also will verify any
differences between tape and disk (if you ask it to). This software took me
about 8 hrs to get a handle on. And I went quite in depth -- excluding files
setting up new defaults and learning all the verification methods. The manual
is about 100 - 200 pages. This backup software will also allow you to backup
while users are using the system.

Thanks again for your help.

Bill Murray
Arrowhead Business Machines

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