We currently have over 180 TB of data sitting on 3590 tapes, we have 2 onsite
3494 ATL's 48 drives total, and 1 offsite (17 miles away) 3494 ATL with 24
drives connected by dark fibre (all of the details escape me right now). We
primarily run our over 800 server classed client backups to diskpools nightly
(2 TB worth), however, for our larger files (Exchange, SQL) we utilize the dual
write feature and write about 1 TB of data to both locations simultaneously
actually faster than we could to disk. Now, before everyone starts to reply
with all the possible disadvantages to this, trust me, we have taken those into
consideration, and that is why we don't back everything up to tape directly.
In the end, my response would have to be, no, I would not want to utilize disk
only, tape technology has come so far, it is a very reliable and economical
solution that can be used along side of disk to give you the best possible
backup/DR solution.
Let me end with this statement...this is only my personal beliefs derived from
my experiences in my environment!!!
Ryan Miller
Principal Financial Group
Tivoli Certified Consultant
Tivoli Storage Manager v4.1
-----Original Message-----
From: Reiss David IT751 (ext-CDI) [mailto:david.reiss AT SIEMENS DOT COM]
Sent: Friday, April 25, 2003 3:02 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Will Hard Drives Edge Out Tape Drives?
I've been reading through the various replies all day long to this little
thread I started yesterday... Now, for my thoughts on the responses.
I wasn't addressing how they setup their little backup system only. Just
how it might fit into the larger Disaster Recovery models with TSM in mind.
And Dan's right. I am thinking very large scale with this. Not something of
only a couple of TB or a few backups. I'm thinking 100's of TB and 1000's of
system backups.
Dan and I go way back (somewhere like 6-8 years now. Geeze. The Internet
bubble was just starting back then, Dan. And you know, you're still a
freak. :-) I know -- I am too.) (And I'll get to that long e-mail you sent
me a few weeks back sometime at home this weekend. I promise. No. Really!)
I was thinking 70 TB of disk for roughly $450 K ain't a bad price. Hook it
all up via some sort of fibre setup to several UNIX servers (AIX or Solaris
depending on the poison of ones choice) as disk pools in TSM... that would
be sweet.
Then, drop a shared 3494 (with 3590 H1A drives) or 3584 (LTO2 drives) (or
even an ADIC 1000 (again LTO2) if one wants to do it on the cheap) off of it
with 2 or 3 frames and you could make several hundard tapes for sending
offsite a day. Between 2 and 4 drives should do it, maybe give it 6 drives
just to overkill it. And since backups are going to large disk pools, you
can backup stgpool to copypools all day long if you want.
Sure, the Rs/6000's or Solaris boxes of reasonable size would add a good
$100 K to $200 K to to the price, but the tape librarys would be cheaper
than 3494 or 3584 with 10+ frames and 30+ drives, and stuff. And the speed
of the disk, even IDE disk, would be much, much faster than any tape. You
could then use disk like this intead of some fast kind of tape (STK 9840 or
IBM 3570) for HSM applications and stuff. Slow Disk is still going to be
faster than Fast Tape.
I can just see a lot of applications of stuff like this cheap disk for
backup into an SAN enviroment. The HSM idea I just meantioned I would think
is only the tip of the iceberg there. Put it in with HP XP1024 or IBM ESS
SAN setups, the good disk for the orginals, and the cheap for backups and
HSM archives, plus whatever kind of play/scratch area for those times when
just throwing 3 TB of disk at something will make everything better (mp3's,
warz and porn colletions, etc. :-)).
I still understand where Patrick Boutilier was coming from with his comments
about supporting soemthing that you designed and built. Getting support
from vendors, IBM, Sun, STK, ADIC, Iron Mountain, etc. can get great to
have. But you don't want to depend on them for everything. Understanding
how all the various hardware and software works toegether is very key to
supporting it. But don't try and reley on SUN to understand IBM tape
libraries, even though lots of folks connect large IBM libraries to SUN
V880's and/or V1280's all the time.
I would want buy in from all my various vendors beforing dropping something
like this poor-mans-ide-raid-backup system in place. I just shove them into
rooms together and make them talk things out. Usually works. Usually.
(Had one issue with IBM hardware 3494 folks, IBM TSM folks, EMC drive folks,
and Brocode and HP just so their knew what the others were up too... all
claimed something was not possible. Turned out that just meant EMC didn't
want to support it, but that it was possible. Figured out a way to make EMC
happy because we had EVERYBODY there, and that made everything work. Of
course, I was sitting by the door to the room with a large lead pipe --
might have entered into it in some way.)
I still like depending on myself, and those I work with, understanding
everything though. Cause I really only want to call for help when I need.
(I like to look like the standard UNIX god of the IT dept. whenever
possible. :-)) It is good to have the top of the line service contracts
behind you when you need them. I like calling IBM, SUN, HP, Brocade,
McData, or whoever the heck up and saying "ESS is borked, send help. I
think the Fibre cards tried to due light speed and might need a replacement.
Or some duct tape in the exact right place anyway.
I find it amazing where ADSM/TSM was just a few years back and where
backups/disaster recovery/large systems have all gotten to now a days, with
TB's of data instead of GB's and sitting at the centers of Fibre attached
SAN's and what-not. Almost running off topic now... So, I'll end this
e-mail now.
Thanks,
David N. Reiss
TSM Support Engineer
david.reiss AT siemens DOT com
407-736-3912
-----Original Message-----
From: Dan Foster [mailto:dsf AT GBLX DOT NET]
Sent: Friday, April 25, 2003 1:55 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Will Hard Drives Edge Out Tape Drives?
Hot Diggety! David E Ehresman was rumored to have written:
> >Just a thought... but 70 TB for $435,000 on disk sounds interesting.
> Just
> >get some small tape libraries for making offsite copy pools.
>
> You're going to use **small** tape libraries for making offsite copies
> of 70TB?
Well...'small' is subjective and might have a different meaning to a
TSM admin working in a very large shop. :) But some quick calculations
lead me to believe this is probably doable with a single LTO-2 library
frame -- 70 TB of uncompressed data yields about 350 tapes; much less
with any sort of reasonable compression (I'd guess 1.75:1 to 2:1).
And that's just for the initial full backups; incrementals might take
a lot less space depending on if they're all client database files or
not. (Not all sites have the money to buy something like TDP or
Veritas's DB Edition or a third party driver to transmit only changed
data)
On the other hand, bottleneck might be diskpool write rate or network
transmit bandwidth rather than tape library size?
-Dan
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