Re: AIT drives

2000-03-09 Thread jakob krabbe



AIT = Advanced Intelligent Tape.

1. I belive this have been discussed before, but please correct me if I'm
wrong when I say Retrospect doesn't take advantage of the chiptechnology
inside those tapes.

2. Would it be wise (possible??) to cycle those tapes in six or eight week
periods? (We have cd backups for the archive.)

3. It is possible to connect and use the drive to a computer that just have
the regular SCSI or dose the drive demand Wide SCSI to work at all?

thanx,

/ jakob


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Re: AIT drives

2000-03-09 Thread Erik Ableson

On Thu, Mar 09, 2000 at 03:24:17PM +0100, jakob krabbe wrote:
 
 
 AIT = Advanced Intelligent Tape.
 
 1. I belive this have been discussed before, but please correct me if I'm
 wrong when I say Retrospect doesn't take advantage of the chiptechnology
 inside those tapes.
Currently Retrospect does not talk to the chips on the tape.  In most cases, the 
utility of the chip is minimal since most of the ideas that people were going to use 
it for are duplicated within Retrospect already (tape indices, etc.)  The one thing 
I'm hoping that Retrospect will do is embed the name of the tape on the chip so that 
you don't have to physically load each tape all the way into the loader to determine 
the tapes that are inserted.  Well - two things - the tape also tracks overall usage 
and error rates on write operations so it would be useful to have a flag that checks 
this data and alerts you when an arbitrary reliability threshold has been exceeded 
before you reuse a tape.

 2. Would it be wise (possible??) to cycle those tapes in six or eight week
 periods? (We have cd backups for the archive.)
Yup - that wouldn't be a problem.  One of the key advantages of the AIT/VXA Advanced 
Metal Evaporative (AME) physical media is that it doesn't degrade with use as rapidly 
as does a DLT or DAT tape that uses a glue binder to attached the magnetic media to 
the physical tape itself.

 3. It is possible to connect and use the drive to a computer that just have
 the regular SCSI or dose the drive demand Wide SCSI to work at all?
You can hook it up to a regular SCSI - you just won't see the high end performance.  
On a beige G3 I've seen throughput up to 200Mb/min using the built-in SCSI port.

There's an excellent white paper available from Spectralogic that covers all the 
technical details quite well at:
http://www.spectralogic.com/resources/brochure/White_Paper_Tape_Drive_Technology.pdf

Cheers,

Erik Ableson


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Re: AIT drives

2000-03-09 Thread Ted Baker

Does anyone have any experience with the LaCie AIT 35 GB/70 GB drives?

I've been using an APS 35/70 AIT drive for ~5 months now on a biege desktop
266MHz G3 running MacOS 9  Retrospect 4.1 (now 4.2) to do nightly backups
on 24 disks on 12 Macs  2 PC's with zero problems from the tape drive.  At
~$2K for the drive plus something like $300 for an Adaptec 2940UW ultra
wide SCSI card it was financially much more attractive than ~$4K for a
35/70 DLT drive.  I had a LaCie 15/30 DLT drive for ~2 years before that 
was very happy with it but the $$$ difference was too much to pass up when
our data storage outgrew the DLT.  Based on my experience to date, I would
certainly recommend this AIT drive  SCSI card.

Regards, Ted



Ted Baker
System/Database Administrator
7 Borehole Bldg., 61 Rt. 9-W
Lamont-Doherty Earth Observatory
   of Columbia University
Palisades,  New York  10964
U.S.A.

914-365-8663  (voice)
914-365-3182  (fax)
[EMAIL PROTECTED]
http://www.ldeo.columbia.edu/BRG





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Re: AIT drives

2000-03-08 Thread Erik Ableson


Yup - we use lots of AITs - not the LaCie ones specifically, but since it's just the 
SONY mechanism in a LaCIE case it should be representative. Currently we're using the 
25/50 tapes but there's very little difference in the new ones.  We have over 4,000 
AIT tapes in current use over the course of the last year and there have been 8 tapes 
that had problems which were all mechanical drive issues.  So that's a damage rate of 
.2% on very high usage backup servers.  Note that that's stricly the tapes that were 
'eaten' as it were.  We've never seen an instance where data written to the media was 
unreadable.

I haven't found a tape system that's completely bulletproof since you are dealing with 
moving physical tapes around a complex path, but the AIT's have been about as close as 
they get.  You might want to look at the VXA tape stuff as well since the media is the 
same as far as I've been able to determine and I think the drive are marginally less 
expensive.

Cheers,

Erik Ableson

On Wed, Mar 08, 2000 at 01:17:17PM -0800, Victor Orly wrote:
 Does anyone have any experience with the LaCie AIT 35 GB/70 GB drives?
 


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