1. Robotics and Tape Drives
Activities
(and non-activities)
31 January 2006

2. Robotics We have 2 sites presently, 513 (large) and 613 (small)
There are 3 library types: IBM 3584, STK SL8500, STK Powderhorn
The largest is the oldest, the 5 plus 5 Powderhorns (60,000 slots)
The newest are the fully configured IBM 3584, and the STK SL8500
These were used (to some extent) in 4Q05, and this will continue in 2006
IBM library is ~6000 slots, ~3 PB max, with IBM 3592 E05 (40)
STK SL8500 is ~7500 slots, will be ~3.5 PB max when T10000s arrive (40)
The Powderhorn libraries are large but only have a future with the T10000.
They do not support the IBM 3592 E05 or LTO drives.
They would represent a useful 30 PB, but end-of-life around 2010…..

3. IBM 3584

4. STK SL8500

5. 513 Powderhorns, IBM 3584

6. 613 Powderhorns

7. Tight(ish) squeeze….

8. Drives We have 5 drive types presently:
IBM 3592 E05, 500 GB, ~100 MB/s, 40 units here but only ~250 cartridges.
STK T10000, 2 ‘fat’ test drives, 500 GB, ~120 MB/s, and 1500 cartridges here.
We expect 40 production T10000.
These IBM and STK products are the newest. Both have been tested 3-4Q 05.
Tests (and limited production) should resume
.. when tape servers are installed
.. STK drives arrive
We also have 8 IBM 3592, 300 GB, ~40 MB/s in a small 3584 (to TSM..)
We also have 6 HP LTO3, 300 GB, ~80 MB/s in the SL8500 system. ??.
The oldest?
STK 9940B, 200 GB and ~30 MB/s, are still the main ‘production’ drive (44)
Retirement starts 3Q06?

9. Vexations
We have the wrong network from disk server to tape server (Gbit ethernet)
We have the wrong FC adapters (new drives will be 4 GB)
We have the wrong disk servers (single 100 MB/s streams not easy)
Do we still have a sensible architecture (disk server layer, tape server layer)?
Next drives will be even faster, more embarrassing, and they are not that far off..
LTO-4 in 1-2Q07
Upgrades of top line drives happens every 2 years or so, for IBM and STK?

10. Is it confusion, or purpose?
Complete IBM library, 40 drives, but very little media
Complete SL8500 library (almost..), planned amount of media, but only test drives
A lot of unused Powderhorn equipment
A shortage of tape servers (hopefully soon to be remedied, but…)
Purpose?
The Powderhorn will support T10000
Both 3584 and SL8500 can support LTO n
It was hoped to test ‘new tape layer architectures’, FC fabrics, …..

11. And, as we move forward ….
Need to use new media, drives, libraries, tape servers for ‘new data’ ASAP
We have 3,000 media, or 1.5 PB, and existing CASTOR is ~4.5 PB.
Need to use new drives (both) for forthcoming Data Challenges
Prepare for call for tenders for more equipment before end 2006
Install this equipment end 2006 or early 2007
… by luck, have a very wide range of options …
NO candidate shown yet to be overwhelmingly good, or to have definitely failed
STILL have LTO n option (3584 or SL8500)
Powderhorns can carry on for longer, but need the T10000

12. Perhaps more difficult….
Need to improve rmcdaemon/smc IBM robot control
Ignore nonsense replies (‘access geometry failure’,…), add remote ‘move media’, remove incorrect drive ‘DOWN’
Need to improve efficiency of drive use in CASTOR (or spend more)
As low as 5% effective for READ, poor for WRITE
This is software, where there is a distinct lack of personnel (and time)
Select ‘drive and media’ for next read/write, and pre-position media, ~60s saved
Writing tapes, fill to near BOT (all drives), ~90s saved
Write all small files in BOT turn-around area, drives look ‘almost’ like 9840
Write small files on fastest label writing drive (IBM?), ~6s saved per file
Read files in order from BOT, NOT sequence order, reads are 2-3 times as fast