DLT or LTO or AIT for new tape drive?

[Folkert Rienstra]

You seem to be unaware that there is a whole range of tape solutions
out there, from unreliable as you claime to very reliable. I personally
pulled several TBs of measurement data from professional tape recently,
without any reading errors at all.

Also the claim that "validating backed up data on tapes is very hard"
is completely bogus. You can do the same you do with any storage
medium: Read it. Also professional tape solutions usually have vastly
superiour error correction and spreading out of the data so that
even data from a torn tape can often be completely recoverd. Of course
if you handle your tape in an amateurish fashion, you can kill it.

But maybe getting somebody that know their stuff to do the backup
is a better option anyways than to follow your advice and have
incompetence as the major risk.

Arno

P.S.: It is "kaput" (german) from french "capot". Not too impressive
spelling it wrong and in capitals.

ROTFLOL !

And that from Arnie "Spelling eRRors R Us" Wagner.

 

[Lady Margaret Thatcher]

Did you notice OP said: "I have a home LAN with about 20 GB online."? He
didn't say that he uses SCSI drive for data. "Industrial-strength" solution
is nice, but not everybody can afford it.

Actually the OP, that's me, does have SCSI drives for data. I get
them used on ebay for a lot less than new, albeit at a premium over
"consumer" IDE. (Ever check out the price and capacity on Western
Digital Raptors?)

If /when I get very serious about video editing and the like, I will
probably set upa SATA RAID for online storage, properly backed up of
course.

 

[Lady Margaret Thatcher]

"Lady Margaret Thatcher" was a transvestite?

We are NOT. Are you coming on to us? And your proclivities?

Yeah, Iron Maggie is dirt poor.

WE are decidedly not impoverished. We can probably buy and sell you
a dozen times.

--Maggie--

 

[Joe Rom King]

Dear Arno

You have to agree with Gartner that at least 40% of tape restore fails.


Yes, it is true that you can improve on this number, but you can do the
same for disk. I just hope you and others can look at this matter in a
non-biased way.

P.S
I think that the correct capitalization of 'German' is more
straightforward.

Joe

 

[Joe Rom King]

Jeremy

Relative Rev Backup gives you the same ability to recover files form 3
days ago, a month ago, and even from a previous year. In addition, it
will consume a backup space that is only slightly bigger than the
original data.

Redundancy is built into this solution by employing two or more backup
disks, each containing a backup history that can go back months or
years. You may also continue with you tape backups, adding another
dimension of fast recovery with Relative Rev Backup.


Network-attached storage, as the backup media is also a viable option.


I hope you get to read more on this product, so you can see my point
(http://www.datamills.com).

Joe

 

[Mike Tomlinson]

You have to agree with Gartner that at least 40% of tape restore fails.

Citation please.

I just hope you and others can look at this matter in a
non-biased way.

We are unbiased. You're the one trying to sell your backup software
(and not being up-front about it.)

 

[Jeremy Boden]

Jeremy

Relative Rev Backup gives you the same ability to recover files form 3
days ago, a month ago, and even from a previous year. In addition, it
will consume a backup space that is only slightly bigger than the
original data.

Redundancy is built into this solution by employing two or more backup
disks, each containing a backup history that can go back months or
years. You may also continue with you tape backups, adding another
dimension of fast recovery with Relative Rev Backup.


Network-attached storage, as the backup media is also a viable option.


I hope you get to read more on this product, so you can see my point
(http://www.datamills.com).

Joe

It sounds interesting - although "40% of tape restores fail" is
obviously wrong.

BTW If you "lose" your OS, can it be restored from the backup?
Are you just saving data or do you get registry backups as well?
Does it support
Are backups interchangeable between different systems?

 

[Joe Rom King]

Mike,
The citation:
http://www.exabyte.com/support/online/documentation/whitepapers/affordabletapeautomation.pdf
" The Gartner Group reports that 40 to 50% of all backups are not
recoverable in full, and that 60%
of all backups fail in general3. Even in large enterprise data centers,
nearly
one quarter of respondents report that 20% or more of their tape-based
recoveries fail4."

Taken from
http://www.exabyte.com/support/online/documentation/whitepapers/affordabletapeautomation.pdf

Also please note that my signature represent the fact that I am with
DataMills.

Joe
Http://www.datamills.com

 

[Joe Rom King]

Jeremey


Here is the citation: The Gartner Group reports that 40 to 50% of all
backups are not recoverable in full, and that 60% of all backups fail
in general3. Even in large enterprise data centers, nearly one quarter
of respondents report that 20% or more of their tape-based recoveries
fail."
Source:http://www.exabyte.com/support/online/documentation/whitepapers/affordabletapeautomation.pdf


This is predominantly a file-based backup. However it does automate the
System State backup, so yes registry, important boot files, as well as
Active Directory data can be backed up.

If I understand your question, so yes the backup is portable. That
means if you loose one computer you can take the disk to another
computer, launch the Recover Settings wizard, and then you can recover
you entire data, or just selected files/folders from any point in time
you choose.

Joe Rom King

 

[Rob Turk]

Jeremey

Here is the citation: The Gartner Group reports that 40 to 50% of all
backups are not recoverable in full, and that 60% of all backups fail
in general3.

If 60% of all backups fail, this means only 40 % of all backups are OK.
If 40% to 50% of all backups are not fully recoverable, then 50% to 60% of
all backups are.

Care to explain how you can get 50% to 60% good restores from only 40% good
backups???

There's lies, damn lies and statistics.

Rob

 

[Nico de Jong]

If 60% of all backups fail, this means only 40 % of all backups are OK.
If 40% to 50% of all backups are not fully recoverable, then 50% to 60% of
all backups are.

Care to explain how you can get 50% to 60% good restores from only 40% good
backups???

There's lies, damn lies and statistics.

Rob

The way I see it, there must be something fishy about either the restore
program or the file system on the system to be restored to.
I've been working with streamers of various kinds since 1986 or so, and my
experience is that tape drives seldomly fail (well, apart from DDS)
I have quite some customers reading /writing tapes very often, so it
cannot
be a general tape-related or drive-related problem. My guess is that the
receiving system prevents the restore of various files, resulting in
unuseable "restored" systems

Nico

 

[Rob Turk]

The way I see it, there must be something fishy about either the restore
program or the file system on the system to be restored to.
I've been working with streamers of various kinds since 1986 or so, and my
experience is that tape drives seldomly fail (well, apart from DDS)
I have quite some customers reading /writing tapes very often, so it
cannot
be a general tape-related or drive-related problem. My guess is that the
receiving system prevents the restore of various files, resulting in
unuseable "restored" systems

Nico

Agreed, many of the so-called 'failures' will probably be due to wrong
selection sets or operator error. The number of 'failures' increases
dramatically if no open file software was used and all reports of incomplete
backups due to locked files were added to the 'failed' category.

My point in the case above however, was that the math doesn't add up. It
claims that they were able to do complete and successful restores from about
20% of 'failed' backups. Smells fishy indeed..

Rob

 

[Rod Speed]

Jeremey

Here is the citation: The Gartner Group reports that
40 to 50% of all backups are not recoverable in full,
and that 60% of all backups fail in general.

Just numbers plucked out of someone's arse without
a shred of rigorous science to substantiate them.

And **** all use tape outside large enterprises now anyway.

Even in large enterprise data centers, nearly one quarter of respondents
report that 20% or more of their tape-based recoveries fail."

Nothing like your original claim.

Source:http://www.exabyte.com/support/online/documentation/whitepapers/affordabletapeautomation.pdf

 

[Rod Speed]

Dear Arno

You have to agree with Gartner that at least 40% of tape restore fails.

No we dont, its a number plucked out of someone's arse.

Yes, it is true that you can improve on this number,
but you can do the same for disk. I just hope you and
others can look at this matter in a non-biased way.

Heard the one about hope springs eternal ?

 

[J. Clarke]

I have a home LAN with about 20 GB online. As I get more into digital
photography and possibly even videos, I expect that amount of storage
can grow quite a lot in the next few years.

My current tape drive is 7/14 GB, and a full backup each month
requires about 4-5 media changes, counting the verify cycle. I would
like to get a drive that allows me to fit say 40 GB (or more) onto one
cartridge. Without bankrupting my Treasury of course.

Should I focus on DLT or AIT or LTO? 68-pin SCSI or even SCA.

All of them work--personally I'd lean toward LTO--the tapes are getting to
be very reasonable for the amount of storage they hold, although the drives
are still expensive.

You're pretty much limited to SCSI, and go 68-pin--SCA is only an advantage
for hot-swapping the drive, otherwise it's a liability because if you don't
have a backplane you have to use an adapter and the adapters I've seen are
all pretty clumsy.

Which format is most reliable and cost-effective, considering both
drive and media cost? What about buying a drive used on eBay? (no
flames please!) Are any of these formats dead-ends like my current 8
mm drive/format?

You can often find bargains in used DLT drives on ebay--the drives are
pretty durable and companies needing more capacity will often surplus out
lower-capacity drives that are in good working order.

I don't need to back up 20 GB in say 30 minutes. I doubt my systems
could even pump out the data fast enough.

That's not really all that high a data transfer rate these days.

(I'm moving to 1 GB LAN for
my newer systems.) A drive with say 40-80 GB native storage would
give me enough "headroom" so that even 2-4 years from now, I should
still be able to do a full backup with one cartridge.

Also, do any of these formats "shoeshine" the tape if the drive isn't
getting data fast enough?

Not really any other way do deal with the situation.

 

[J. Clarke]

Perce

Tape has its own vulnerabilities:

Humidity will ruin any tape. Placing the tape near an electromagnet
source such as generator or a big electric engine are great ways to
implement a "secure delete". Placing the tape is a closed car in
the summer time, is another dead end road for tapes. Tapes are
vulnerable to wear and tear, about 30-50 cycles before they die on you.

DLT was tested to 500,000 cycles and was found to still be _improving_ at
that point. If your experience has been with Travan and DDS don't assume
that they are typical.

I know a customer that lost all of his data because his tape drive was
near a copy machine causing the toner particles in the air to make all
of his tapes unreadable.

Try shuttling a tape drive while it writes to tapes, especially if you
tilt them in a way that causes radial forces, and the tape will be
KPUT.

"Shuttling"? Would you care to define that term?

Statistics shows that 40%-60% of tape restores fails. Validating the
backed up data on tapes are very hard, sentencing your organization to
a life at the foothill of an active volcano.

It's not any more difficult than any other media--read the tape and compare
the contents to what is on the disk.

Disk is vulnerable to sever drop (can be easily solved with a cushioned
transport packaging), but is mostly immune to all above mentioned items
because of the hermetically sealed environment it operates in (dirt and
electromagnetic wise).

Disk are not hermetically sealed, and I would not be surprised at all if
toner would make it through the filter. There is no particular magnetic
shielding on disks--equidistant from a large magnet disk and tape should be
affected about the same.

The logical conclusion is not to rely on a single backup media, be it
tape or disk.

In this you are correct if the requirement is truly mission-critical.

Now for your question regarding generations and number of media:
Relative Rev Backup has a unique management algorithm that makes sure
you can have many months worth of backup generations stored on each
backup disk. However, if you have at least two backup disks in daily
rotation, any damage to any disk will result in loosing the backup of
the last day only. (Same effect as damaging the last tape).

That is what I mean by robust and cost effective at the same time.

For a small system using disks as removable media can be cost effective, but
regardless of the kind of software you're using you should use the same
multiple-generation with offsite storage strategy that you would use with
tape.

 

[Curious George]

but the tapes are a little pricey so it's not the bargain it may first
appear.

Well, nothing against Exabyte, but their drives and media, while good,
aren't as bullet-proof, never-fail as my earlier QIC drives, including
a 1 GB native Tandberg drive. But that format seemed to becoming
obsolete, and newer drives couldn't even read some of the older QIC
formats.

compatibility was one issue with QIC. The other is that
"bullet-proof, never-fail" was not typically used to describe them.

I would like to avoid that scenario again.



Sounds good. I'll have to check it out. Which vendor is preferred?
Or to be avoided.



Ah. I hadn't realized that DLT is dead-ending.

It isn't really. SDLT replaces DLT but some backwards-compatability
remains. There are so many DLT systems in service that there should
be no problems coming by tapes & parts for the next few years (which
is all you should expect anyway).

LTO might be nice.
If it is master of the enterprise, that tells me it's reliable. But
it also tells me that it could be too expensive for me, and the native
transfer rates to keep an LTO drive "full" might be more than my LAN
could possibly supply.

I previous asked about "shoeshining" with different formats. Is AIT
less prone to shoeshining than the other formats?

That's software & configuration specific except for some LTO's that
can adjust speed to compensate.

 

[Nico de Jong]

Well, nothing against Exabyte, but their drives and media, while good,

compatibility was one issue with QIC. The other is that
"bullet-proof, never-fail" was not typically used to describe them.

In my +20 years of media conversion, the most stable media type is clearly
the DC600 aka Tandberg (and others).
It is clear that there are compatibility issues, as the number of tracks has
changed, and so has the density.
Typically (apart from SLR7) drives are 2 generations backward
write-compatible, and 4-5 generations read-compatible.
Nico

 

[Curious George]

In my +20 years of media conversion, the most stable media type is clearly
the DC600 aka Tandberg (and others).
It is clear that there are compatibility issues, as the number of tracks has
changed, and so has the density.
Typically (apart from SLR7) drives are 2 generations backward
write-compatible, and 4-5 generations read-compatible.
Nico

I don't doubt her good experiences with a Tandberg. I think you would
agree, though, "QIC" is a very broad category indeed.

 

[Nico de Jong]

I don't doubt her good experiences with a Tandberg. I think you would
agree, though, "QIC" is a very broad category indeed.

You'right. I'm thinking exclusively on the DC600 drives working on SCSI,
like Tandberg and Archive Viper series (2060 and 2150 IIRC)). Although the
Viper drives are not quite as stable as the Tandberg, I never had
media-related problems, apart from 2 cases where the tape broke.

On the opposite site, I have bad experiences with DDS3 drives. A case comes
to mind where I had to do so forensics work for the State Police. I mounted
the tape in a new drive, and took off the partition with the backup. No
problem. Then the customer came back, and wanted more. I can't recall if it
was another partition or just a "loglist" or whatever. I mounted the tape
again, but nothing happend. Retry, again nothing. I then took the lid of the
drive, and saw that the tape was wound around the motor. Totally destructed,
and I tossed the drive too.
I was not very popular with the State Police, as the data had to used in
court...

Nico