From ilug-admin@linux.ie Wed Mar 20
11:33:47 2002
Date: Wed, 20 Mar 2002 11:32:49 -0800
To: ilug@linux.ie
Cc: Niall O Broin niall@linux.ie
Subject: Re: [ILUG] backup options...
From: Rick Moen rick@linuxmafia.com
Quoting Niall O Broin (niall@linux.ie):
> Ultrium (as previously mentioned) has 100GB native
capacity, drive
> costs $3000 (best price on pricewatch, so you'll probably
pay somewhat
> more) and cartridges are $85 + - claims to backup 108GB per
hour which
> is of course with mythical compression of 2:1 so actually
claim is
> 54GB / hour which is 15 Mbyte/second which is pretty nippy
:-) I read
> on review of this which said that the speed claim is not
marketing
> bullshit and that it is actually very fast.
LTO ("Ultrium") is pretty damned good. For those who can
afford the
price of admission. <sigh> In its class, you have SDLT and
damned
little else.
One point of comparison is of course helical scan vs linear
vs. other.
As noted previously, helical scan wears tapes and heads
rapidly.
Media type Head type Nom. capacity Nom. speed Vendors 8mm helical scan 2GB/5GB 500kB/s Exabyte, Tandberg "AME" 8mm helical scan 20-60GB[1] 3 & 8MB[2] Exabyte DLT3XL linear serpentine 15GB 1.5MB/s DEC, Quantum DLT4 linear serpentine 20-40GB 3-5MB/s Quantum, others? SDLT linear serpentine 110GB 6MB/s Quantum, Tandberg DDS2 helical scan 2GB/4GB 500kB/s HP and others DDS3 helical scan 12GB 1.5MB/s HP and others DDS4 helical scan 20GB 3MB/s Various DLT7000 linear serpentine 35GB 5MB/s Quantum AIT helical scan 25-50GB 6MB/s[3] Sony LTO linear serpentine 100GB 15MB/s IBM, Seagate ADR2 linear serpentine 120GB 5MB/s OnStream
Also relevant: Cost of tapes, cost of drives, cost of
replacement
heads, service life....
Be sure to consult The Linux Tape Device Certification
Program, before
buying any drive: http://www.linuxtapecert.org/
[1] When used in M2-type drives. M1 does 2.5-20GB.
[2] Thanks to Ray Kelly for furnishing AME speed figures.
[3] That's with AIT2 drives. AIT3 drives do 12MB/s, with 100GB
capacity.
--
Cheers, "Learning Java has been a slow and tortuous process for
me. Every
Rick Moen few minutes, I start screaming 'No, you fools!' and
have to go
rick@linuxmafia.com read
something from _Structure and Interpretation of
Computer Programs_ to de-stress." -- The Cube,
www.forum3000.org