On Saturday 21 September 2002 08:15, Niall O Broin wrote:
>On Fri, Sep 20, 2002 at 09:19:43PM -0400, Gene Heskett wrote:
>> seen it work in practice here, nor do I need it, but my system
>> is only 46gigs, which amanda cheerfully uses about half a 4gig
>> tape per nightly run to back it all up on a 1 week dumpcycle.
>
>Gene - I've seen you mention this a few times before and I'm
> mildly curious. You've a 1 week dumpcycle, and I'll assume
> runspercycle is 7.
Correct.
> You said that amanda uses about half a 4gig
> tape per nightly run which is 14 gig in a week. Now even assuming
> that you have miniscule level 1 dumps, are you getting such good
> compression from gzip that you get 46G (at least) of disk into
> 14G of tape ? Or is the 46G the amount of disk space you're
> backing, but it's not actually all used ?
This latter case Niall. Not all disklist entries are compressed,
but of those that I do compress, the output is maybe 20% of the
inputs size, so the gzipping works pretty good where it can. My
space utilization according to df is around 50% for each partition
except /, which when I formatted this drive, I figured 2 gigs was
enough. I've had to play space patrol there several times because
gimp if you don't correct it, puts its working files in ~/user,
100-400 megs per image modification, and I've been building each
new amanda in /home/amanda, all of which is on /. So eventually I
have to go "clean house" so to speak.
> Mind you, I have to say
> that I have been very impressed with the usage amanda makes of
> tape - I'd say that this is one of its best features, esp. now
> that the cost of disk storage is now only about the same as the
> cost of tape to back it up.
>
>> of the DDS2 is the price of the tapes, they are almost a
>> non-issue at less than 50 bucks a ten pack on ebay.
>
>Even so - $5 per 4G tape is $1.25 a tape, which is > IDE disk
> costs now, and this price per gig doesn't seem to vary hugely as
> you go to bigger capacities. I think I paid about 9 EURO (a few
> cents less than $9 at current rates) the last time I bought DDS 3
> tapes (12 G). DDS4 (20 GB) cost 18 EUR, 40 GB DLT is 63 EURO, 60
> GB ADR is 60 EUR. Bottom line is tape has become relatively
> expensive, and amanda can get very good mileage (byteage ?) from
> your tapes.
Thats pretty much true, and the last time we needed a backup
solution that could cover our small business data at the tv station
where I'm the now semi-retired CE, we didn't do it with tape, but
with a linux based software raid array based on 4 each 160 gig
maxtors, each one on the primary headers of a pair of promise
cards, and using rsync as the operating engine. Speed limited only
by the 100baseT network, its classed by us as somewhere between
fast and damned fast, beating tape speeds by orders of magnitude.
Its been up about 8 months now, needed for recovery several times
and worked flawlessly. rsync beats a samba link because it only
backs up those bytes that change, and it apparently does all the
timestamp stuffs samba doesn't. But thats a minor consideration
since with the exception of the news dept (12 machines total there
at last count), all other servers are now linux based, and
openoffice for windows is weaseling its way into the clients of the
system so eventually the underlying os becomes linux and nobody
notices.
At least thats the plan, and its worked for about 4 workstations so
far although I haven't been keeping track since July 1 when they
gave me dinner and the Rolex. I'm down to a one nighter a week at
the transmitter, working a bit of wood, catching up on my computin,
shootin & fishin and such. <VBG>
--
Cheers Niall, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz 512M
99.15% setiathome rank, not too shabby for a WV hillbilly
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