Greg brings up a number of good points and implores the backup vendors to
get into the discussion.
I have been travelling this week, and whilst I always monitor email, this
is my first chance sit down and take the time to properly respond. Mark K.
has already made some excellent comments, I would like to address the
questions thusly.
The thread started when someone posted a message about IBM aiming to have a
400GB disk by 2003. Interestingly, when I posted a month or so ago that
IBM had released a 48GB NOTEBOOK disk drive, no one got scared. The
notebook disk drive of 2003 should be at about 200GB, as the capacities
have been doubling every year for a long time.
However, Greg and several others have mixed up home computers backup issues
and corporate backup issues. He further entangled the issue by bringing in
solid state memory as a possible backup solution.
Currently the biggest problem with home computers is the almost complete
absence of backups. As an example, on the plane last coming back from
wherever I was this week, the gentleman seated next to me mentioned he had
just lost all his digital pictures because his disk drive imploded. I
asked him about his backup strategy, to which the answer was, as it
invariably is, "What backup strategy?" His camera is a 3MP model meaning
that each picture is between 250KB to 1.2MB in size, depending on the level
of compression. Several months or years of such pictures will occupy a
shipload of storage. I explained the easiest, cheapest and most reliable
way of backing this up would be either a CD-R or a DVD-R device. He could
get a CD-R device for a few hundred dollars and buying top-quality CD-R
(not CD-RW) media. Then it is just a matter of properly archiving the
files on a regular basis.
When it comes to home backup, unlike corporate backups, files are
accumulated and rarely modified. You download MP3, PDF, JPG, MOV, AVI or
other such files. These are big and accumulate very quickly. The
operating system and virtually all the applications come on CD-ROM or
DVD-ROM and do not really need to be backed up. In the end, the files on
which you work are email related and some documents that you have. Even
the digital pictures you take are usually modified quickly and can then
archived. If you keep up with archiving to CD-R or DVD-R and just worry
about the 1 gigabyte or much less of ongoing projects, your backup problems
are reduced immensely.
Solid state memory currently comes in a few formats and this will probably
increase in numbers. The most popular format, by far, is the CompactFlash
medium. Currently you can have CF cards approaching 512MB. These are very
expensive, but as with everything else in this industry, except for wages
and taxes, the prices are always falling as performance (capacity, speed,
resolution, etc...) increases. There is still a disparity between the
solid state storage performance and the rotating media storage performance.
The Lexar website (www.digitalfilm.com), home of the best CF memory (IMHO)
shows that a 12X USB 320MB media retails for $900. That is about $3 per
megabyte. There are cheaper sources of CF memory, and smaller capacity
with reduced speeds cost a lot less, maybe even close to $1 per megabyte
(www.sandisk.com $1.50/MB.) I selected Lexar for the size and also to try
to approach transfer rates of a disk drive.
The Dirt Cheap Drives web site (www.dirtcheapdrives.com), shows an 80GB
Maxtor drive for $238. This is the same drive I have installed in my
docking station. This is about $3 per gigabyte. One thousand times less
than CF. BTW, CF is the cheapest and most capacious solid state medium.
Now for corporate storage. First off, the description of RAID arrays does
not match my understanding of the current state of hot-swappable or
hot-pluggable disk drives. In such an array, disk drives that go bad are
simply pulled out and replaced on the fly. The RAID array controller then
syncs up the new drives automatically. The system never need know a drive
was replaced and the mirrors or whatever are never broken. The exposure is
when you have more than one drive go bad in the same array, at the same
time.
In properly equipped data centers, lightning whilst still a problem does
not need be a critical issue for the computer room. I lived in NC for a
while, home of the second most popular dumping ground for cloud-borne stray
electrons and we took a hit directly on the battery farm of the UPS. The
computers were not affected, but we had to switch to raw power for a while
as they replaced the batteries.
The issue of backup and especially restore is one of money. How much money
do you want to spend, or how much does it cost to be without your data for
a time? Given an unlimited budget, one can duplicate or triplicate the
environment providing automatic switchover in case of problems. As the
budget reduces, so do the options. We have RAID arrays of various
capabilities, followed by mirrored disks, JBODs, and finally single disk
drives. Backups still need to be performed, but the raison d'être of the
backups change depending on the duplication in place. At the low end, the
backup is the only recovery option both near and long term, same as with
the JBOD. When you start mirroring and RAIDing, the backups are more for
archiving, meeting government-mandated requirements and protection against
operator or program errors. This is when the need for on-line backups is
greatest. There are tape devices that go much faster than DLT drives and
they are much more expensive. Robotic libraries are used to prevent
operator error and cut down on the number of tape swaps and mount time.
All these things cost money.
As I said, backup and recovery is really affected by the budget. It just
depends on your priorities.
Kind regards,
Denys. . .
Denys Beauchemin
HICOMP
(800) 323-8863 (281) 288-7438 Fax: (281) 355-6879
denys at hicomp.com www.hicomp.com
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