In article <[email hidden]>,
T said:Except for the fact that tape is only recoverabel in about 69% of the
actual cases.
Where did you get that number? 69% is way too low for modern tape media.
I have been doing backups to tape for many years and I have never
encountered a situation where we cannot get data back off a bad tape. I
do occasionally find bad tapes in my inventory, but I take them out of
circulation before much data gets written to them. In fact, that
situation happened this morning.
Quoted message said:Every month we dump the contents of that 1TB drive to an external unit
and then store it in our archives. We cycles 13 drives, one is pulled
and kept at the end of a year.
The problem we ran into was that tape could NOT keep up with the volume
of information on some of our servers. It gets prohibitively more
expensive the higher you go on tape capacity.
That depends. My problem is that I can't get data to my 22 tape drives
fast enough. All my tape drives are capable of writing data much faster
than they receive data. I plan to address that problem this summer.
Quoted message said:Put it this way, the hard drives we use are 350GB and cost around $100,
a DLT cartridge for 80GB is near $70. So in this case tape is most
definitely NOT cheaper.
DLT media is old technology and there's no way a DLT cartridge costs as
much as $70. The latest DLT media can hold 160GB of data native and
320GB compressed and you can buy a single cartridge from
http://www.cdw.com for $46.00, but buying in bulk will yield lower
prices.
Two weeks ago, I received a tape new library that uses LTO-3 cartridges,
which hold around 400GB native and 800GB compressed. I also have an
order pending in my purchasing department for 150 LTO-3 cartridges at
around $60 each, if I remember correctly.
Quoted message said:The other thing is we looked at studies that showed the lifetime of
tapes. They're pretty fussy beasts. Hard drives that aren't powered on
actually last LONGER.
It depends on the media. Tape isn't powered on either. My main tape
library uses Sony S-AIT1 media, which costs around $110 per cartridge,
but I also get around 800GB per cartridge (and I can measure this fairly
accurately). I can write a 600GB disk image to a single tape cartridge,
whereas I know of no off-the-shelf disk drives that can hold a disk
image that large.
My primary tape library has provision for 925 data cartridges, plus 11
cleaning cartridges. That's a huge amount of storage and adding on
another cabinet to hold 300 more cartridges is fairly inexpensive. I
also have never failed an internal or external disaster recovery audit
due to bad tapes, or any other reason involving the tape hardware I
manage. That is saying a lot because I am subject to internal and
external audits every month to verify that we can recover from a major
server failure. I can, and do, boast of a 100% success rate.
In terms of cost, the typical organization will find that in order to do
backups, they will spend a minimum of five times the amount they spent
to house the primary copy of their data. Doing backups is an expensive
proposition when you do it for several terabytes of data across hundreds
of computers nightly and have to meet lots of regulatory mandates and
also avoid the dreaded situation of losing backup data.
