LTO is the most commonly used tape drive technology among Amanda users. When
we conducted an extensive survey of Amanda usage, almost 40% of
respondents said they use LTO tape drives:
http://wiki.zmanda.com/index.php/Results_of_Amanda_Users_Survey_2006
Considering the price difference between LTO4 ($4,600 per drive and $100 per
tape) and LTO 3 ($2,700 per drive and $50 per tape), I would go with LTO3
because you get the same price per GB of data on tape, but spend less money
upfront with LTO3.
You can get an excellent StorageTek SL24 (24 tape slots) autoloader for
$7,000 from Sun, and you can try it for 60 days before buying. A similar LTO
autoloader from Dell would cost you around $5,000 if you catch a sale.
However, Dell does not offer a trial, and people often mention less than
positive experience with Dell's support, especially for non-server and
OEM-ed products, e.g. printers or autoloaders.
Regards
-------------
Dmitri Joukovski
-----Original Message-----
From: owner-amanda-users AT amanda DOT org [mailto:owner-amanda-users AT amanda
DOT org]
On Behalf Of Chris Hoogendyk
Sent: Wednesday, October 15, 2008 9:35 AM
To: Seann Clark
Cc: amanda-users AT amanda DOT org
Subject: Re: Tape drives -- Recommendations?
Seann Clark wrote:
> All,
>
> I am fairly new to the list, not so new to Amanda (I usually troll
> IRC when I am looking for help half the time) but I want to poll the
> group for suggestions to aid in what I am looking into as well. I have
> a system currently that has 3.12TB of data, which I would like to
> start backing up regularly, and soon will increase that to a larger
> number as well. I am looking for a good service tape drive that can
> take care of the physical offloading of backups, and that plays well
> with Amanda. I have an old SCSI HP SureStore that I can never get to
> really back up to (Pity it was a nice drive for the time, esp when I
> was maxed at 700GB) though it can read the tapes, write to the tapes
> through Amanda, it just dies partially through and freezes up the
> drive. What I am after though is a backup system that is tape based. I
> would prefer non SCSI, but I can work around that.
>
>
> The other alternative I am looking into is getting a large external
> case and cramming it full of 1TB hard drives and using that as backup,
> but I would like a tape system that works well. I haven't gotten that
> portion to work too well in the past, but since it was a first time
> doing it, I am very sure it was a fatal user error that was preventing
> it from happening.
It has a huge amount to do with budget.
Being in a budget conscious department, I settled on a Sony LIB-162A5.
Ballpark cost around $5k. Less if you get good discounts. It uses AIT5
tapes (400G native), comes with one drive but can take a second, holds
16 tapes. The somewhat lower cost comes from being a carousel mechanism
that is less complex than the typical robots. That also means it is more
reliable, but less expandable than the popular lines of robotic libraries.
I think most people are going with LTO. I chose AIT because I liked the
technology. It isn't as fast as LTO, but it doesn't shoe shine. I hear
plenty of horror stories of people who get a really fast LTO drive and
find that they aren't getting any throughput. That's actually because
the computer they configure to go with it can't maintain the data
throughput that the tape needs, so the tape goes into shoe shining, and
the throughput drops even further to dismal levels. Of course, if budget
is not an issue, and if you understand your hardware configuration well,
then you will configure a backup server that has the capacity to pump
data to the tape and keep it going. I have no trouble keeping the AIT5
going at its full rated speed.
Why not SCSI? Most of the tape libraries are SCSI (either directly SCSI
or via SAS or Fibre Channel). Mine is LVD320 SCSI. I'm not sure what
alternative you are thinking of. Whatever you choose, you have to think
about throughput. Figure out how much data you are planning to transfer
and then calculate optimal times. You won't typically get optimal, but
it will put you in the right ballpark. Be sure to account for bits
versus bytes in the various transfer technologies. Network stuff is
going to be bits, internal bus transfers are typically bytes. So, I run
Gigabit network and my AIT5 will do 25MBytes.
Fortunately, Amanda will smooth the demand over your dump cycle. So, if
you are trying to do 3.12TB total, and you break that up into many
DLE's, then you may only be averaging 500GB a night or even less,
depending on your dump cycle. I'm sure you already know that, but it is
a significant part of the calculations and a real advantage over other
backup software.
Of course, it certainly doesn't hurt to do both vtapes and tapes. I'm a
big fan of redundancy, which is why I run a long tape cycle and have
dual holding disks.
--
---------------
Chris Hoogendyk
-
O__ ---- Systems Administrator
c/ /'_ --- Biology & Geology Departments
(*) \(*) -- 140 Morrill Science Center
~~~~~~~~~~ - University of Massachusetts, Amherst
<hoogendyk AT bio.umass DOT edu>
---------------
Erdös 4
|
