Tape Drive Testing IBM 3592

IBM 3592 tape drive Maximum native data rate of 40 MB/s 60GB (not for us) and 300 GB IBM 3592 cartridge 8 meters/s high-speed search Compatible with IBM tape library, not STK tape library (Powderhorn) 1Gps/2Gps fibre channel connection 3592 tape drive 3584 library

Initial test infrastructure (now 8 ‘mid-range` servers) Tape Server IBM 3584 Tape Library Fiber Qlogic Fiber Channel Bus Adapter IBM 3592 Tape Drive

Over 125,000 mount/dismount cycles performed, no errors ‘Mechanical` tests Over 125,000 mount/dismount cycles performed, no errors Test mechanical reliability of drive / media: some cartridges now mounted > 4000 times, no errors Perform random file reads on selected tapes and media: superseded by CASTOR/ALICE MDC6 operation

Performance tests General characteristics Drive mount (from slot) 3.2 s Time to access VOL1 20.9 s Rewind 0.01 s Unload 22.0 s Dismount (to slot) 2.8 s Write very small ‘labelled file’ 0.2s CM chip, RF I/O, 4096 bytes, part of cartridge 512 tracks in 64 sets of 8 8 m/s high speed search 20,000 load/unload cycle lifetime for cartridge 300 full file passes lifetime for cartridge Measurements made over 88 cartridges in the 3584

`Performance` tests (without CASTOR) Read and write to tape Use UNIX commands mt, dd only Similar tests are carried out on all new types of drive to be used at CERN to measure… Capacity of cartridge and blocksize, 1-256K Capacity of cartridge and filesize Write datarate with blocksize 1-256K Write datarate with blocksize 1-17K Write datarate with very small blocksize 1-1024 bytes Read datarate with blocksize 1-256K Reproducibility of maximum capacity, filling a single cartridge Variation in maximum capacity, filling different cartridges Labelled files, 'position to file' and rewind timings Blocks, 'position to block' and rewind timings Apparent sizes of small labelled files, from rewind timings Time to create small labelled files Compression write datarate with blocksize 1-256K Compression read datarate with blocksize 1-256K Compression write datarate with filesize Verification of legal FC command execution …..and so on and so on…….

`Performance` tests (using CASTOR) Verify the functioning of the CASTOR and CASTOR related functions: tape_up tape unit standard testing for production utility tplabel tape labelling utility dumptape tape dumping (scanning) utility stagein tape reading utility stagewrt tape writing utility repack move CASTOR file from tape and reclaim utilities

`Performance` tests: some typical examples.. No compression, 1K=1024, 1M=1048576 Data transfer rate (write)

`Performance` tests: some typical examples.. Compressed data transfer rate (write) Use compression, 1K=1024, 1M=1048576 dd if=/dev/zero ibs=256k of=/dev/nst0 obs=256k count=n

`Performance` tests: some typical examples.. ‘Labelled’ file position/rewind times ‘user’ files on tape, each ~25 MB (100 blocks of 256K), simulated labels The 64 serpentine track sets (32 ‘out’, 32 ‘back) show clearly! Command mt -f /dev/nst0 fsf n Command mt -f /dev/nst0 rewind

Check returned information, timing, command acceptance Functionality Tests Go through the set of commands available on the SCSI standard Check returned information, timing, command acceptance SCSI 3 COMMANDS: Change Definition, Compare, Copy, Copy and Verify, Display Message, Erase, Format Medium, Inquiry, Load/Unload, Locate , Log Select, Log Sense, Mode Select (6), Mode Select (10), Mode Sense (6), Mode Sense (10), Persistent Reserve In, Persistent Reserve Out, Prevent/Allow Medium Removal, Read, Read Attribute, Read Block Limits, Read Buffer, Read Position, Read Reverse, Receive Diagnostic Results, Recover Buffered Data, Release Unit (6), Release Unit (10), Report Density Support LUNs, Request Sense Unit (6), Reserve Unit (10), Rewind, Send Diagnostic, Set Capacity, Space, Test Unit Ready, Verify, Write, Write Attribute, Write Buffer, Write Filemarks IBM 3592 TESTED COMMANDS Display Message, Erase, Inquiry, Load/Unload, Locate , Log Select, Log Sense, Mode Select (10), Mode Sense (10), Persistent Reserve In, Persistent Reserve Out, Prevent/Allow Medium Removal, Read, Read Block Limits, Read Buffer, Read Position, Receive Diagnostic Results, Recover Buffered Data, Release Unit (6), Report Density Support, Report LUNs, Request Sense Unit (6), Reserve Unit (6), Rewind, Send Diagnostic, Space, Test Unit Ready, Write, Write Buffer, Write Filemarks OK

Test Infrastructure

Test Scenarios 1) IBM tape driver and IBMtapeutil (interactive/command line mode) 2) Linux tape driver and cernTapeTestUtil (interactive/command line mode)

Analysis of Results

Conclusions IBM 3592 Tape Drive SCSI commands OK cernTapeTestUtil more than a test tool for tape drives; also a diagnostics tool .... provides access to vital information on tape drive and media statistics and status cernTapeTestUtil works on STK 9840, STK 9940, HP LT02 as well as 3592 and will be used on any new equipment that will arrive to be tested Use of a SCSI/fibre channel analyzer permits a precise logging of results and this can be used for all our drives