AIT drives

CDR & DVD media as backup I find terrifying, since the variability of
branded media is varying so hugely between Japan & India. The latter
can backup, verify & read-restore ok - but in a few months fail to do so.

I wonder how many people actually restore from backups to test them?
Probably very few, yet it is so critical to do so - beyond plain verify.

Magneto Optical does stand a chance of 30yrs and even 100yrs
being a phase-change magnetic/curie-point-heat system. However,
I agree I would "assume few yrs" as opposed to what marketing say.
CDR/DVD have too many variables and are more frisbee backups.
Data that's so important for decades is often very small in size, and
so easy to re-restore to verify & implement in most reliable media.


Too many businesses DO skimp on backup quality.
o Even for small businesses, a lost week of data can cost 10,000ukp+
o More often, lost data can cost the survivability of the company
---- lost customers, lost business, lost reputation/brand/marketing
---- lost ability of the company to actually function

So the cost, be it 1,000ukp or 2,000ukp of a good backup device is
really irrelevant. Most small businesses waste far more than that in
a year anyway. So if the data is important, quality backups count.

An alternative for very small businesses & home use is to use an
Internet based backup system - however they're often quite pricey.
I'm still not convinced about their LT viability (& so the backups!).
--
Dorothy Bradbury

I should add to my comment re MO reliability:
"I agree I would "assume few yrs" as opposed to what marketing say"

for 2 reasons:
o It *is* just a media disk out of a factory - it can vary
---- whatever the drive & media ISO standards
---- whatever the drive h/w write-&-instant-verify error checking
o Media faults do occur
---- I've had some bad Fujitsu disks (incredulously)
------ albeit a formatting error, all in the same cluster due to an abort
---- a couple of years ago, Philips shipped a batch of bad MO disks
------ that was a real defect, albeit auto-recoverable-from

The "bad" batch was found to have the same defect:
o Every MO disk like a hard disk has redundant sectors
---- I recall it is 9 or 13 of them
o Most MO disks ship with 0 defects, a few perhaps 1-2
---- so there is inherent recoverability
---- MO writes & then verifies the write on the next rpm (hence speed)
---- if there's a problem it uses one of the other areas of the disk
o The Philips disks had a tiny 5um or 10um defect on the disk
---- all were replaced under lifetime media warranty
---- no data was lost, the media self-recovered

MO disks are polycarbonate in shuttered shells, and rely on a quite
powerful laser to heat the magnetic material above its Curie point,
then & only then can the polarity of the bit be changed.

However, any media can vary - similar defect risks exist with tape,
plus a few more environmental ones for those sloppy in their handling.
Human error still has its share of the "Ooops" in data loss after all :-)
--
Dorothy Bradbury
www.stores.ebay.co.uk/panaflofan for fans, books & other items
http://homepage.ntlworld.com/dorothy...ry/panaflo.htm (Direct)

Given that a new DLT IV tape can now be had for under £26 compared
to a AIT1 tape of £38, DLT quickly becomes cheaper than AIT.

AIT is offered as an alternative for DLT, when it's really not so great.

It still comes back to the original problem of 1 drive & 1 media type.
I prefer 2 backup devices & 2 backup media for critical data.

o The only really solid tape is DLT & upwards from there
o The only media which is truly engineered to be reliable without being
tape is magneto optical - CD & DVD are not as good as magneto optical


Well unless there has been a radical capacity and speed increase they
are just too small and too slow.

Re MO, for anything above SOHO & small business, yes.
For online archiving they can have their uses - 5.25" jukeboxes, however
there is a superior technology to 5.25" MO and offers potential (UDO).

IBM/Plasmon blue-laser UDO - 30GB (120GB eventually) & cheaper media.
However, that's playing catchup with DLT on size & still pricey media (price
per byte may be much lower than MO, despite still being phase-change, but
the disks are far higher capacity so the net price per disk is probably
higher).

I think MO/UDO are better for online archiving or small data-set backups,
both are prime candidates for jukebox storage altho disk isn't pricey
anymore.

DLT is out of the range of SOHO, but AIT isn't such a great substitute.
VX2 has it's following, but many of the "alternative" tape systems are poor.

Optical for SOHO via CDR/DVD is subject to variable media, leaving MO.
DVD-RAM makes me nervous about LT support. MO in 3.5" has just one
supplier of the drives, altho huge uptake in Japan. The 5.25" has more,
but UDO may way displace it thro cost of media & sheer capacity.

DAT I loathe and still suspect it's where many bad experiences of tape
technology came from - Digital Audio Tape is very different to DLT.

If tape - go DLT, if optical - go MO.
If capacity/business - go DLT, if SOHO MO is cheap even on Ebay.

Actually Ebay has both on sale - for hypercritical small-data-sets I would
still add an MO drive. A sealed, new, 640MB MO is 25ukp on Ebay. Comes
down to the budget, application and criticality of the data concerned.

AIT is above DAT, but somehow I don't find that so comforting.
DAT advocates will be along shortly, ok I recall DDS1/2, later improved :-)
--
Dorothy Bradbury

On Thu, 18 Dec 2003 20:32:13 -0000, "dorothy.bradbury"
wrote:

CDR & DVD media as backup I find terrifying, since the variability of
branded media is varying so hugely between Japan & India. The latter
can backup, verify & read-restore ok - but in a few months fail to do so.

Yep, CDR & DVD media can be used if you have high qaulity media and a
good storage location, but as you say, can you be sure the supplier
hasn't just outsourced the production to an poor quality manufacturer.
For storage a cool dry dark place is best. If someone is using coaster
quality disc for backups then they deserve what they get.

I wonder how many people actually restore from backups to test them?
Probably very few, yet it is so critical to do so - beyond plain verify.

Outside of business I expect not many. I've always worked at places
that regularly test backups.


Magneto Optical does stand a chance of 30yrs and even 100yrs
being a phase-change magnetic/curie-point-heat system. However,
I agree I would "assume few yrs" as opposed to what marketing say.
CDR/DVD have too many variables and are more frisbee backups.
Data that's so important for decades is often very small in size, and
so easy to re-restore to verify & implement in most reliable media.

What sort of capacity MO drives do you work with though? For our
backups you are talking terrabytes.

Too many businesses DO skimp on backup quality.
o Even for small businesses, a lost week of data can cost 10,000ukp+
o More often, lost data can cost the survivability of the company
---- lost customers, lost business, lost reputation/brand/marketing
---- lost ability of the company to actually function

Yes, but thats a backup policy issue rather than the media. You could
backup to floppies if you were disciplined enough :-)

So the cost, be it 1,000ukp or 2,000ukp of a good backup device is
really irrelevant. Most small businesses waste far more than that in
a year anyway. So if the data is important, quality backups count.

Yes a couple of grand is quite acceptable for a backup device. Usual
backup devices I've worked with you can multiply that by 10 to 100.
And anything in that region has always been TK, DLT or 1/2 inch tape.

An alternative for very small businesses & home use is to use an
Internet based backup system - however they're often quite pricey.
I'm still not convinced about their LT viability (& so the backups!).

Yep, putting your backups in the hands of a remote service that a) you
don't know the quality of their backups b) can't gaurantee 24/7 access
to (what if your internet connection is down) is not clever. Its
advantage would be as a extra remote backup if say your building burns
down and you have to relocate & can get internet access. Too many ifs
for my liking.

On Fri, 19 Dec 2003 00:36:55 -0000, "dorothy.bradbury"
wrote:

-
-DLT is out of the range of SOHO, but AIT isn't such a great substitute.
-VX2 has it's following, but many of the "alternative" tape systems are poor.
-

Interesting debate. We still have several customers who store small databases on
1/4 inch QIC tapes on Tandberg SLR drives. Incredibly reliable.


-Rob
robatwork at mail dot com

On Fri, 19 Dec 2003 10:30:37 +0000, Rob S
wrote:

On Fri, 19 Dec 2003 00:36:55 -0000, "dorothy.bradbury"
wrote:

-
-DLT is out of the range of SOHO, but AIT isn't such a great substitute.
-VX2 has it's following, but many of the "alternative" tape systems are poor.
-

Interesting debate. We still have several customers who store small databases on
1/4 inch QIC tapes on Tandberg SLR drives. Incredibly reliable.

I've still got an old DEC (as it was at the time) TK tape with VMS on
that worked very recently at least (as backups are only as valid as
the last good read AFAIM concerned).

Jonathan Buzzard wrote:
You really need to factor in the cost of tapes. As a DLT IV tape
can be had for £26 brand new with the VAT, and will hold 40GB
native where an AIT1 tape will cost £38 and only hold 35GB native
you can quickly get to DLT being cheaper.

Comparing new drives, it seems the cheapest AIT1 drives are around £470 ex
VAT, the cheapest DLT around £770 ex VAT. If, for the moment, we assume the
sizes are equal (I realise they aren't, but 14% isn't *that* much, and not
every tape would be full), that means that if I save £12/tape with DLT I
have to buy 30 or more tapes to recoup the ~£350 extra I would spend on the
DLT drive. Right now, I don't think I need that many tapes - I'd though
10-12 would be a suitable starting point, 1 per day and a handful over for
last week's/last month's/three months/six months backup...

It is wildly more reliable,

I'm not trying to be picky, but can you provide a reference for this claim?

and has many more sold devices than AIT which might also be a
consideration.

I don't doubt that there's a better second hand market in DLT, but I don't
want to go that route.

What's it for? If it is for home use have you considered picking up a
DLT 35/70 drive cheap on eBay? There are plenty of drives being sold
of as companies upgrade to SDLT and the like. These drives where
built like bricks so are unlikely to give problems with a little home
use.

I really need a warranty on the drive; I'm just not prepared to go to Ebay -
I've read/experienced too many horror stories.

James

dorothy.bradbury wrote:
Given that a new DLT IV tape can now be had for under £26 compared
to a AIT1 tape of £38, DLT quickly becomes cheaper than AIT.

AIT is offered as an alternative for DLT, when it's really not so
great.

I'm not trying to be devil's advocate here, but what exactly is wrong with
AIT, and what's so good about DLT? I'm quite happy to assume that you get
more for your ~£800 than you do for ~£500, but why is AIT really that bad?

I'm wondering if I detect some kind of preference for non-proprietary
solutions - is that what annoys people about AIT?

James

On Fri, 19 Dec 2003 18:31:31 +0100, James wrote:

dorothy.bradbury wrote:
Given that a new DLT IV tape can now be had for under £26 compared
to a AIT1 tape of £38, DLT quickly becomes cheaper than AIT.

AIT is offered as an alternative for DLT, when it's really not so
great.

I'm not trying to be devil's advocate here, but what exactly is wrong with
AIT, and what's so good about DLT? I'm quite happy to assume that you get
more for your ~£800 than you do for ~£500, but why is AIT really that bad?

It is an 8mm derivative and as such a helical scan technology.
*ALL* helical scan tape technologies are considered by many
to be a bit naff. The problem is compared to linear tape
technologies, with helical scan the tape follows much more
convoluted paths, have much more complicated mechanics,
tape head speed is much higher, and usually the bit density
on the tape is higher as well. Helical scan technologies
include DAT, 8mm/Exabyte, VXA, Mammoth and AIT.

There is also safety in numbers with 90% of the market being DLT.

I'm wondering if I detect some kind of preference for non-proprietary
solutions - is that what annoys people about AIT?

Well DLT is fairly proprietary. Until recently only Quantum
made drives (they have come to an arrangement where Tandberg
are a second source), with lots of tape manufactures. The
latter leads to competitive pricing on tapes.

Now all I need is a lottery win to finance that SDLT 600 drive.
Native capacity of 300GB a tape and native transfer speed of
36MB/s. Who said disks where faster than tapes?

JAB.

--
Jonathan A. Buzzard Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom. Tel: +44 1661-832195

On Fri, 19 Dec 2003 10:30:37 +0000, Rob S wrote:

On Fri, 19 Dec 2003 00:36:55 -0000, "dorothy.bradbury"
wrote:

-
-DLT is out of the range of SOHO, but AIT isn't such a great substitute.
-VX2 has it's following, but many of the "alternative" tape systems are poor.
-

Interesting debate. We still have several customers who store small databases on
1/4 inch QIC tapes on Tandberg SLR drives. Incredibly reliable.


Not surprising a linear tape technology with comparatively low
bit densities. At least compared to helical scan technologies,
but not to DLT. The cartridges are rather large compared to
DLT if you ask me due to the fact it has a take up spool
in the cartridge.

JAB.

--
Jonathan A. Buzzard Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom. Tel: +44 1661-832195