We just went though a similar exercise. We have LTO2 drives and
libraries at remote sites, and are very satisfied with them, so we were
more than willing to make the change if needed. In the end we decided to
leave our 4 3494 libraries in place and replace the 3590E drives with
3592s.
We considered ripping out the whole thing and replacing it with
LTO2 libraries/tapes, but when we factored in the cost of the new
library/drives/computer-room rework/man-hours/etc, the cost came out
very close to replacing the 3590 drives with 3592's.
So, we ponied up the money to upgrade all 46 drives. The process
of moving the 375TB of data to the new media took about 3 months, using
all the spare tape cycles to run "move data" processes. It was kind of a
balancing act, as you have up upgrade a whole frame at a time, and with
8 TSM servers sharing 4 libraries, making it non-disruptive was a
challenge.
In the end, we ended up losing 82 files (non-copypooled data, on
purpose), out of about 600 million backed up files. A very impressive
statistic for tape backups. Luckily the files were non-critical (thus
justifying the non-copypooled status of the data)
We also were having tape issues with the 3590Es, but not as bad
as yours. Since the upgrade of the drives, we have had no problems, but
with new drives and media, you would expect that. The data capacities
are GREAT with the density of data on the 3592 tapes being 10X that of
3590E tapes. It really has given me some breathing room in my libraries
and lets me sleep better at night.
Ben
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
James R Owen
Sent: Monday, February 21, 2005 5:51 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: ? replace aging 3590 tapes/drives w/ LTO ?
We're looking for experienced advice considering whether to
a) upgrade our 3590 E1A drives to H1A drives and reuse
our aging 3590 tapes for net gain of 50% more tape space
b) discard 3494 and 3590 technology and replace w/ LTO-2 or
LTO-3 drives and media, expanding our existing 3584 ATL's
currently filled w/ LTO-1 media and mixed LTO-1/2 drives.
If you have considered or done one of these conversions, we would like
to hear from or talk with you. If you don't feel like writing a reply,
please send me a phone# and we'll try to call you.
Yale University started using 3590 tapes 8 years ago in 1996.
We now have two 3494 ATL's, each w/ six 3590 E1A drives, and about 4000
J tape cartridges, most of them 6-8 years old.
The warranted life of a 3590 cartridge is 10 years, so...
we are wondering what other sites are thinking/doing about your aging
3590 media and hardware.
To date, our actual 3590 media failures are insignificant:
about 40-50 tapes over the 8 years or 1-2% real failed media.
[But how much longer can we expect them to last: 5-10 yrs?]
That's eliminating all of the "false" failures where the 3590 drive
actually was at fault; if the tape passes an AUDit Volume and doesn't
get errors on another drive, we UPDate the volume back to ReadWrite
status and keep on using it, unless it fails again! We also re-attach
leader blocks, if they get pulled off, and continue to using the tape if
it loads OK. We've only had to fix 6 of those, but 3 became detached
during the past 2 weeks!
We've had a rough two weeks with one of our 3494 ATL's, but problems
seem to occur in fits and spurts. After a few months w/ no problems,
we've called IBM 8 times during the past week to service 3590 problems
in our busiest 3494 (but had no problems w/ the other one!)
During the busiest hours of each afternoon (migrating small clients'
backups from disk to collocated 3590 tapes) each of the six 3590 drives
mounts (and dismounts) 20 tapes/hr or 120 tapes/hr for the 3494 robot.
The library is typically that busy for 5-7 hours each day, then much
less busy for the rest of the day and night, mostly doing 3590 tape
reclamations.
Please advise, if you have experience to share.
Thanks for your help.
--
Jim.Owen AT Yale DOT Edu (203.432.6693)
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