[SAGE-AU] Re: [Talk] Reality check...
thogard at knotty.abnormal.com
Thu Sep 12 10:05:33 EST 2002
Since backups have been brought up again.... heres my take on
the major issues from a smallish IT company.
I've been using IDE drives for backups for years. I've worked
enough places with the big backup kit to know the ups and downs of
that as well. I also never liked the failure rates of any of the
lower cost tape solutions.
I work for a small company (about 20 people) and our IT is split
between Windows and Unix. On the windows side, most daily files
are stored on a network drive. Those network drives are backedup
to a special pc that has a fancy hot swap IDE raid motherboard.
One of the drives is removed every day and taken home, while the
other stays on site. We have three day drive rotations and some
complex system of writing all that data to CD's so that all the
data more than a week old should be on at least two forms of backup
media and any thing older than a month should be on three.
On the Unix side has a backup server running linux and its got a
large internal drive and a hot swap bay. It stores the dump output.
Level 3 every day and level 0 once a week by cron. Every once in
a while, I put in a removable drive and copy the internal hard drive
to it. Since my drives are all the same, I can umount /backup and
dd it to /remove and pick up the drive a few hours later. I've
been hot swaping IDE drives in the box for two years without any
issues and I've only lost one drive in the cheap swap meet removable
caddies in the last three years. This may seem a bit sloppy but
there are other issues here. The 1st is we have all the data
someplace else (we pump changes over a 128k link). The hard drives
on the unix backups are mostly there in case someone does an rm on
the wrong file and I don't want to pull it over the slow link. The
second is we are an electronics shop. We can swap boards around if
something gets fried and we have spare boards. The third issue is
that this involves backups of backups of backups. The 4th issue
is the bosses are pack-rats. They have every sales order on paper
form since '74 but wont buy a good tape drive. Their attitude is
they have spent lots of money on tapes and tape drives over the
years and they can't read most of the tapes they have.
A few months ago I made a change to the linux box I use to backup
the unix systems. I got a firewire card ($75) and single external
box ($150). I took the small IDE to firewire convert card out and
installed it behind the IDE removable rack. I wired the switch on
the rack to power the converter and the hard drive so now I have
a fully hot swapable fireware drive as far as the pc is concerned.
The major reason for doing this is that I can't get linux 2.4 to
hot swap correctly. Under 2.0/2.2 we had a small program that would
do an iotcl that would reread the drive settings and everything was
happy. 2.4 broke the small program and didn't autodetect the drive
changes so the firewire is a cleaner solution.
There are two reasons to make copies of data. One is to Archive
and the other is Backup. Backups cover the place buring down to
recovering the proposal that Bob just deleted while "cleaing up".
Archives are there when the Tax office comes knocking. In the long
run, backups make poor archives and archives make poor backups.
A company also needs to address the issues of offsite vs on site
backups as well as theft of data. Where I work, we have had a few
people put large rocks in the windows and grab any PC's they can.
One of the directors got his PC stolen from his home just a few
months ago and it contained sourcecode that wasn't backed up. At
least it was only a few days work. All of our computers where we
keep onsite backups are installed in racks (www.ridge.com.au make
very good cases for this). Since many Aussie insurance policies
no longer cover PC theft, we have to assume that they are a very
hot item. Being in an industrial park on a 3 day weekend also makes
you a target. Our solution is an alarm company, video cameras,
servers bolted in racks, servers with security cables in racks and
better looking PCs not locked down.
I suspect that tape backup will be dead inside about 5 years. Every
company that currently makes tape drives is having major problems
in sales and are downsizing. Any company that is willing to spend
more than about $4000/mo on backups can move their data offsite
without using tapes and the small guys are going removable drives
or CD-rom or DVD+w. That will leave a smaller number of customers
looking for the tape solutions.
> Quoting John Stern (J.Stern at bom.gov.au):
> > Daniel O'Connor wrote:
> > > > IDEA:
> > > > The cost of DLT & LTO tape media is ~$3/Gb.
> > > > The cost of commodity IDE drives is ~$1-2/Gb. IDE enclosures with
> > > > either Firewire or USB are cheap & readily available.
> > >
> > > IDE costs around $3/Gb too.
> > 9940's (60GB) cost about $240 an 80GB seagate is ~$210.
> > I don't know the pricing on LTO or DLT.
> In our last order of LTO's, we got around 250 carts for $40k, which
> makes each tape around $160. We're getting 150 - 200 GB per cart which
> makes the cost per GB vary between 80c and $1.
> We're also getting read/write speeds of around 25MB / sec per drive,
> which is a little out of the bounds of IDE.
> Mind you, this sort of infrastructure doesn't come cheap - especially
> once some software is involved - a 160GB drive in a firewire enclosure
> looks like a darn good solution for home from what I can see, as long as
> its taken somewhere else once the data is on it...
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