Hi Allen,

I've been VERY pleased/surprised at how durable IBM LTOx drives have
been overall.  LTO2 gave less problems than LTO1, and I think LTO3 has
had fewer problems than LTO2.   For many sites they are an EXCELLENT
value and totally appropriate for TSM use.  

On the other hand, I doubt there are many TSM installations running
their LTO drives truly at a 100% duty cycle.  

In my experience, there is NO QUESTION that the 359x drives are tougher.
I think most people are just willing to deal with occasional drive
outages in return for lower initial cost.

Things that I have personally experienced:

1) When LTO drives fail, they don't get repaired.  The CE just comes in
and replaces them.  They are essentially "BIC" drives - plastic parts,
no refills.  

2) LTO MEDIA aren't nearly as tough as the 3592 media.  The tape has to
be pulled out of the cartridge by a little pin.  If that pin doesn't get
reseated properly (or if the tape has been jiggled too much during
shipping), the cartridge will jam in the drive on the next load. 

3) If a cartridge gets jammed in a drive, the CE has to come remove it
for you.  He/she has to open up the drive and try to un-thread the
cartridge manually.  There is about a 60% chance you will lose the
drive, the cartridge, or both (see also #1 above).  When we had this
happen once (LTO2), we lost the drive, but the CE tried to save the
cartridge for us.  We loaded that cartrdige into another drive, and it
promptly jammed that drive, too.  Had to replace the 2nd drive as well,
throw the cartridge away.  For LTO3, I believe they have replaced the
threading motor, so this shouldn't happen as often.  

4) If you look at TCO instead of initial cost, the 3592's may not cost
you significantly more.  What different sites pay differs these days
(all drives from all manufacturers are often heavily discounted).
Monthly maint for LTO may be HIGHER than for 359x (see #1 and #3
above!).

5) Another issue around TCO:  When you get ready to upgrade to get more
capacity, you have to replace BOTH the drives and media for LTO to get
additional capacity in your library.  For the 3592's, the next upgrade
is supposed to be drive-only, no replacement of media required.  For
many sites, the media is a SIGNIFICANT part of the cost.


So what I tell people who ask the question and haven't bought yet:

a) If you are going to push the drives really hard (in my opinion, that
means more than 12 hours per day), or if you can't afford to have a
drive down, or if you don't have the PEOPLE time to mess with failed
drives, you should be buying 3592's, because they are designed to take a
beating.

b) If you are located a long way from your IBM maintenance personnel,
don't even think about buying LTO; they WILL break.

c) As an alternative to (b) above, if you need 10 drives, buy 11 and
just expect one to be down at any given time.

d) If you have DLT drives now, you will be pleased and amazed at how
much more durable the LTO drives are.

e) If you have 3590 drives now, you would NOT be pleased at the relative
durability of the LTO drives.

f) I have never had a customer who bought 359x technology and later said
"gee, that was a bad choice".

My opinion, and nobody else's...

Wanda  

   




 

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Allen S. Rout
Sent: Wednesday, August 02, 2006 10:37 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Tape Drive Choices: What, and why?

Hi, all.

I'm looking into what choices folks have made for their tape drives,
and why they picked what they did.  I'm really happy with what I've
got, but I figure that state is perpetuated by questioning it, rather
than settling in.


I'm running 3590s (on the way out) and 3592s.  The capacity is close
to the top per-cartridge (500G raw per cart), and the speed is quite
good, ~80GB/s.

When we added the 1-gen 3592s a few years ago, seek speed was an
important difference between that and the then current LTO2; I
understand that LTO3 has made up some ground there but not all the
way.

My drives are getting a duty cycle approaching 100%; there are very
few times of the day I don't have jobs waiting in line for them.  My
SE is kind of nervous about them; he says we're mean to them. :)

I am given to understand that this kind of treatment tears LTO3s
apart; they aren't designed for that kind of 24x7 usage.

In a nutshell, I love my 3592s, I run them constantly and have
essentially no maintenance issues with them.  I've got some of them in
a remote installation ~300 miles away, and run them with confidence,
so far borne out. (8 months of production)



So, any opinions?  Love stories for LTO3 or that sun whatever-1000 ?
Hate stories?



- Allen S. Rout