I had to look into this recently for a backup and archival solution - indeed
I had a couple of questions answered by this group.
The general consensus was to use SCSI for everything other than a home
The three most current tape technologies are DAT and DLT, with AIT
(developed by IBM) being the most recent. I've seen comments in various *nix
groups that AIT is too new a technology and too expensive for most needs.
Each DAT tape holds 10-40GB, and has a typical duty cycle of 10%-20% . DLT
tapes hold 20-80GB each, and have a duty cycle of 80-100%. I don't have
figure to hand on the AIT stuff.
HP has a nice diagram that indicates the scaling of DAT, DLT and DLT
libraries - http://www.hp.com/storage/chrt_auto.html
Back in November, Kenn posted to ILUG
(in an O'Reilly book, at that...) that the different drive technologies
are designed for different duty cycles:
AIT 10% (!!!)
Given transfer rates of the following (compressed):
DDS-3 5 GB/h (according to last night's backup)
DLT 7000 36 GB/h (according to O'Reilly)
AIT 22 GB/h (according to O'Reilly)
this gives daily throughput of:
DDS-3 24 GB/day
DLT 7000 864 GB/day
AIT 52 GB/day
In the end we chose a 20-40BG DLT with a Dell Poweredge 2300. The Dell
internal DAT unit was about £500, the DLT unit was about £1500 - all ex VAT.
Right now we don't need the full power of the DLT, but we will within a
matter of months, and it's nice to know it's there from the start.
In reading the newsgroups, some commented that DAT tapes can mangle
themselves and DLT tapes rarely do - but this all seemed to be anecdotal and
I couldn't find any research to back it up. Your mileage may vary.
----- Original Message -----
From: Colin Whittaker <grimnar at redbrick.dcu.ie>
To: ilug <ilug at linux.ie>
Sent: Saturday, January 08, 2000 1:39 AM
Subject: [ILUG] Re: tape drives
> Vincent Cunniffe stated the following on Fri, Jan 07, 2000 at 04:02:05PM
> > I'm considering getting a tape drive to backup stuff from my
> > Linux server, which is reliable as hell but does have about 20
> > gig of stuff on it that's not currently backed up :-/ 
> > So, any recommendations as to :
> > IDE vs SCSI
> > Brands?
> > Technologies to get/avoid?
> > Driver availability under Linux?
>> HP scsi dat drive, get upto 24 gigs compressed onto a dds3 tape
> the new dds4drives are supposed to do 40 compressed.
>> HP drives seem to be pretty reliable.
> | "Crystalline perfection is brittle" |
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> List maintainer: listmaster at linux.ie>
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