VXA tape flaw

(Arthur Begun) writes:
By the way, some of the obnoxious posts here assumed my data was life
or death, etc, etc, etc. It was not. Life or death data is on a
mirrored file server and backed up to tape.

Since you were talking about spending kilobucks at a data recovery
place to get your tape put back together after you screwed it up, it
would logically follow that the data is important. If it's not
important, then why are you wasting your time posting here? You
screwed up your backup but you have another one, fine, use the other
one this time, learn something from the screwed up backup experience
and do it right next time.

Arthur Begun wrote:
And it
concerns me that somehow when a backup was appended to media, the end
result was the loss of all previous backups. Been using Backup Exec
for almost 2 decades and never have seen it before. And for many
years that was using some very primitive drives from Colorado, Conner,
and others. VXA promotes itself as more reliable than others yet
magically a tape is wiped out. And mine wasn't the only one according
to the 2001 post by a Retrospect user.

Hi Arthur,

This is getting a bit tiresome ( I know, I don't have to keep reading
this thread...).
You keep repeating that the VXA wiped out your tape. I'm sure the data
is still on the tape. What happened was that BE was writing to the
header when the machine hung, thus corrupting the header and now BE
doesn't know where the data is on the tape. To me, this is a
questionable strategy for a backup program to use. This would have
happened if you were using any tape drive. You happened to be using a
VXA drive. Rather than blaming someone/something, I'd recommend just
realizing that very occasionally bad things happen and you need to plan
on that and move on. If you absolutely need to put blame somewhere, I'd
point to Backup Exec and Retrospect. After all, what was the tape drive
supposed to do when the machine was rebooted? Go back and magically fix
the header? I would hope that if BE is using this strategy that they
would have a tool you could use to fix the header. Something analogous
to chkdsk for DOS disks.

I realize that you were just trying to warn people that VXA is bad
technology. A lot of people here believe that you are incorrect and are
trying to set things straight for future readers who come across this
thread.

Good luck,

Steve
__________________________________________________ ___________
Steve Cousins Email:
Research Associate Phone: (207) 581-4302
Ocean Modeling Group
School of Marine Sciences 208 Libby Hall,
University of Maine Orono ME 04469

So if your building burns down goodbye data.

Actually, I walk a tape out of here every couple of weeks (should
do it every week !). And, I am moving from tape backup to external
200 GB USB2 harddrives. One of those is always at home in the
closet also.

By the way, some of the obnoxious posts here assumed my data was life
or death, etc, etc, etc. It was not. Life or death data is on a

Good to hear that !

mirrored file server and backed up to tape. This data was from a
workstation. According to statistics passed around by magazines, 80%
of companies don't backup workstations at all. I did. And it

Sorry to hear that. I use the same backup strategy, no matter what
the media. I backup the entire network to each device. No
incrementals. I do not believe in them as I have been burned before.
I use robocopy on the hard drives to speed up the backup so
identical files are not recopied.

concerns me that somehow when a backup was appended to media, the end
result was the loss of all previous backups. Been using Backup Exec
for almost 2 decades and never have seen it before. And for many

Yup, does not sound very good either. But, my point was that
do not have single points of failure in your backup. I have 3
spinning hard drives on three seperate PCs that I can retrieve any
file from as my first layer of backup. Then I have a weekly tape
or a weekly external hard drive. So I will just have the external
hard drive as I am dropping the tape.

Good luck,
Lynn

Paul Rubin wrote in message ...
(Arthur Begun) writes:
By the way, some of the obnoxious posts here assumed my data was life
or death, etc, etc, etc. It was not. Life or death data is on a
mirrored file server and backed up to tape.

Since you were talking about spending kilobucks at a data recovery
place to get your tape put back together after you screwed it up, it
would logically follow that the data is important. If it's not
important, then why are you wasting your time posting here? You
screwed up your backup but you have another one, fine, use the other
one this time, learn something from the screwed up backup experience
and do it right next time.

I spent a good part of last night reading thru hundred's of newsgroup
posts at Veritas Backup Exec website. They have a fine newsgroup,
appears to be completely open and uncensored, with help provided by
Veritas and users. And it has great searching abilities. Searched on
"header" and anything else I could think of that might be related to
what happened. The newsgroup goes back about 5 years with thousands
of posts of problems with various versions of Backup Exec. NOT A
SINGLE REPORT OF A TAPE READING ZERO OR BLANK AFTER AN APPENDED
BACKUP. NOT ONE!!! NOT A SINGLE ONE. CLEAR ENUF TO YOU GUYS?????

When I first heard about VXA from Ecrix I thought that VXA technology
was the brightest idea since sliced bread. I would like to still
believe so but Exabyte doesn't provide a open newsgroup for
discussions of their drives so it is impossible to know if my data
loss is a rare or frequent event. You can believe what you want to
but it is highly unlikely that I found a new defect in Backup Exec.

I never thought Backup Exec was the greatest program in the world but
I'm sure that the header is written as a series and if it hung during
writing the last of it all I would have lost was information on the
last backup which I don't really care about. The header information
on the previous backups should have remained. In fact there were
several posts about freeze-ups while updating a header and no mention
of prior data loss as a result.

Malcolm Weir wrote in message . ..
On 29 Jan 2004 13:49:24 -0800, (Arthur Begun)
wrote:

Paul Rubin wrote in message ...

[ Snip ]

Just in case anyone is reading this thread, check this guys posts in
Google. Basically he is a troll. And if the VXA format is not
capable of reliable appended backups, that fact should be specified in
documentation.

Paul is not a troll, or at least is not always one, and as far as I
remember doesn't troll here. I don't agree with some things he
writes, but he has much more of a clue and contributes more than you,
Arthur Begun, does.

Arthur, you are just angry because YOU messed up your backups. Shame
on you. Blaming the hardware because YOU were stupid enough to try to
use only one tape for a critical backup is even worse!

Malc.

I love it when stupid people call people stupid. Who said it was a
critical backup? But you damn right that I want to know where the
hell the data went because I've checked Backup Exec's newsgroup with
thousand's of posts from users and an extensive search indicates this
has never happened to a Backup Exec user before. Yet it did happen to
a Retrospect user. The only thing in common was we both were using a
VXA drive. You must be feeling pretty stupid.

On 30 Jan 2004 12:20:29 -0800, (Arthur Begun)
wrote:

[ Snip ]

Paul is not a troll, or at least is not always one, and as far as I
remember doesn't troll here. I don't agree with some things he
writes, but he has much more of a clue and contributes more than you,
Arthur Begun, does.

Arthur, you are just angry because YOU messed up your backups. Shame
on you. Blaming the hardware because YOU were stupid enough to try to
use only one tape for a critical backup is even worse!

I love it when stupid people call people stupid. Who said it was a
critical backup?

If it wasn't, why the hell are you complaining?

Seriously?

If the backup failed, do it again, enjoy.

But you damn right that I want to know where the
hell the data went because I've checked Backup Exec's newsgroup with
thousand's of posts from users and an extensive search indicates this
has never happened to a Backup Exec user before.

At the risk of pointing out YOUR stupidity, all that proves is that
no-one has REPORTED before. Possibly the phenomena happened and
no-one reported it (because, say, they just re-did the backup).
Possibly the window in which it can happen is small. Possibly the
other users took note of the error message displayed and have a better
idea of what happened that you do?

Yet it did happen to a Retrospect user.

And you know that... how? Was the error the same? Oh, wait, you
don't know what the error was!

The only thing in common was we both were using a
VXA drive. You must be feeling pretty stupid.

Well, actually, I'm fine. Now, why, exactly, do you care about the
contents of that non-critical backup?

Take your time!

Malc.

On 29 Jan 2004 20:05:12 -0800, (Arthur Begun)
wrote:

"Lynn McGuire" wrote in message ...
If you are considering a VXA tape drive from exabyte (formerly ecrix)
you should be aware of a fatal flaw. Even though ads show a tape
soaking in a cup of coffee and a claim that the data is still
recoverable, the tape header is extremely fragile. If you are doing a
backup and the computer freezes and requires a hardboot as the header

Rule #1 - one tape, one backup (do not put mutiple backups on one tape)

Rule #2 - one backup, one tape (buy a big enough tape drive for your backup)

Rule #3 - use multiple backup devices like hard drives in addition to your
tape drive - that way the single point of failure (the tape) will
not kill you

We use a weekly backup to a VXA-2 tape drive in addition to three
200 GB hard drives that are daily backed up to on the network. Only
one of the hard drives is on the file server.

Lynn

So if your building burns down goodbye data.

Errr... how do you conclude that the tape is located in the building?

Or, indeed, that the entirety of the network is located in a single
building?

By the way, some of the obnoxious posts here assumed my data was life
or death, etc, etc, etc. It was not.

So why complain?

[ Snip ]

And mine wasn't the only one according
to the 2001 post by a Retrospect user.

So, hypothetically, let's assume some VXA problem. The frequency of
occurrence of this alleged problem is, umm, once every three years?
And when it does occur, the symptoms are that the loaded tape becomes
(effectively) blank... but every other tape is unaffected. And the
alleged issue occurs on writing, not reading.

Hmm.... not seeing a huge problem here!

Malc.

"Arthur Begun" wrote in message
om...

I spent a good part of last night reading thru hundred's of newsgroup
posts at Veritas Backup Exec website. They have a fine newsgroup,
appears to be completely open and uncensored, with help provided by
Veritas and users. And it has great searching abilities. Searched on
"header" and anything else I could think of that might be related to
what happened. The newsgroup goes back about 5 years with thousands
of posts of problems with various versions of Backup Exec. NOT A
SINGLE REPORT OF A TAPE READING ZERO OR BLANK AFTER AN APPENDED
BACKUP. NOT ONE!!! NOT A SINGLE ONE. CLEAR ENUF TO YOU GUYS?????


Interesting... My 3 minutes on the Veritas web site brought me to the
following hit:
http://seer.support.veritas.com/docs/233735.htm

So although you found no hits of anyone discussing a similar issue, Veritas
has discovered such a flaw in their software before. Please note the line
that says "NOTE: These errors are not completely indicative of the problem
and could be displayed during other operations"

Also read: "In rare situations, it is possible for a COM communication link
to be broken prematurely." Your system hung and/or you cut power before the
backup was complete. I think we can all agree that at that point COM
communications was gone too.

I'm sure you will come back with an argument like "my BE was a newer version
so that issue was fixed". Probably yes. Maybe not. Maybe another instance
still lurks. Does that mean everyone in the world should be warned that
BackupExec has a critical flaw? I don't think so.

We all know that software has bugs, hardware fails, and problems occur. It's
a fact of life, you and I are not going to change much about that. Now
please go erase the tape, redo your backup and get on with your life.

Rob

In article ,
Arthur Begun wrote:
After Backup Exec backups the files, it writes to the header. I
presume it adds some information to the front that tells the tape
where the last backup began and ended. Seems to me that if this
operation was interupted, the newly appended backup would expected to
be lost but information on previous backups should not be wiped out.

I would expect that any information in the header being updated may be
corrupted or destroyed if an error occurs while writing a header. In
fact I would not expect any backup software to rewrite a header at all,
I would expect it to chain the backup set information so it never was
in a position where a write failure could potentially overwrite
"frozen" data.

The more I learn about commercial backup software the more glad I am that
I'm using AMANDA.

--
I've seen things you people can't imagine. Chimneysweeps on fire over the roofs
of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All
these things will be lost in time, like chalk-paintings in the rain. `-_-'
Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U`

In article ,
Arthur Begun wrote:
Just in case anyone is reading this thread, check this guys posts in
Google. Basically he is a troll. And if the VXA format is not
capable of reliable appended backups, that fact should be specified in
documentation.

I have had my differences with him in the past, but that doesn't mean
he's not correct in this case. If Backup Exec rewrites the header of
the tape then it's NOT simply doing an append operation. Rewriting the
header is not something any backup software should do, or at the very
least it should do it in such a way that it can reconstruct the header
from chained snapshots that it makes as it goes along.

--
I've seen things you people can't imagine. Chimneysweeps on fire over the roofs
of London. I've watched kite-strings glitter in the sun at Hyde Park Gate. All
these things will be lost in time, like chalk-paintings in the rain. `-_-'
Time for your nap. | Peter da Silva | Har du kramat din varg, idag? 'U`