Jon Aquilina wrote:
in my case where money isnt an issue wouldnt it be better for me to
build a raid backup array? i understand your reasoning. im still
studying and fairly new in the higher education of IT so when i start
working ill keep what you mentioned to heart. only problem is that where
i am located in europe things are more expensive here. another random
idea why not create a raided backup array backed up to tape? is it
possible to do a tape back up of data thata being written to disk instantly
It's absolutely possible to do a mirrored write to RAID spinning media
and also to tape. In a perfect world, where I don't have budget
constraints, that's how I'd achieve my third tier of backup. The real
reason we bother with tiered storage and multiple copies, however,
remains "disaster recovery". One theory says that simply having two
copies in the data center is enough. Experience teaches that, for true
disaster recovery, one needs a pretty recent off-site copy, that is
unlikely to be disrupted by an event in one locale. I know of one
company that mirrors disks over 100 miles from their r&d/corporate
offices via multiple 10gigabit paths, with two feeds for power, a diesel
generator, and a battery plant to keep things running. In their main
site, they have disk and tape. Offsite, they have another disk copy.
And last week's tapes.
In higher-education IT, one tends to have a lot of budget constraints.
Funding agencies want accountability and don't seem to just give us
hardware dollars for the asking, although it often seems that way when
someone who's not seeking said funding, watches the process. Therefore,
money IS a problem and we have to determine the best way to keep things
going while optimizing expenses.
Different approaches don't mean we're disagreeing with you, however. MY
primary backup is spinning (RAID) disk. I'd like to expand to LTO tape
with robotics but my funding agencies have not yet seen the wisdom of
this, and think my use of disk is just fine. Until we have a problem
(and problems are almost guaranteed) and get in trouble for not having
incorporated tape (or another, different, technology) in our backup
plan, I don't expect to see funds for it. In fact, when we do get in
trouble, I see us redirecting already allocated funds rather than
getting new funds, to accomplish this. Just understand that redirecting
funding for a new hardware implementation requires sponsor approval,
and if they don't understand "Why?" it can get messy.
gerry
On Mon, Jul 7, 2008 at 5:05 AM, Steve Cousins <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
From: "Jon Aquilina"
this is slightly off topic but im just wondering why spend
thousands of
dollars when u can just setup another server and backup
everything to a
raided hard drive array?
Another RAID system helps but only if it is located somewhere else.
The main reason we backup is for disaster recovery. One nice thing
about tape is that you can take the tapes to another location easily
or put them in a fire safe.
Another reason is that RAID systems don't scale up as easily as a
tape system. Our library has two 15 tape magazines that can be
removed and replaced. It costs about $750 to buy 15 new tapes plus a
magazine. That's not too bad for 6 TB of storage (uncompressed, with
HW compression we get about 9 TB). Plus it takes practically no time
to start using it.
The library wasn't really that expensive when we bought it either.
Somewhere around $7500. At the time we bought that we were using 400
GB drives in our RAID systems at $300 each. To build a server with 5
TiB (usable) of RAID storage at the time was about $7000. The tapes
were more expensive then (about $100 each) but for about $10,500 we
got 12 TB of tape storage (library plus 30 tapes). To get roughly
the same of disk storage would have been about $14K. So right off
the bat tape was cheaper. Plus it is so much easier to manage. I
like the idea of snapshots and using rsync plus links is a crafty
idea but I sleep better knowing that I have a "real" (one that I can
carry around) backup of our data in our safe.
Steve
--
Jonathan Aquilina
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Gerry Creager -- [EMAIL PROTECTED]
Texas Mesonet -- AATLT, Texas A&M University
Cell: 979.229.5301 Office: 979.458.4020 FAX: 979.862.3983
Office: 1700 Research Parkway Ste 160, TAMU, College Station, TX 77843
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