Hugo HEPiX Fall 2005 Testing High Performance Tape Drives HEPiX FALL 2005 Data Services Section

Hugo HEPiX Fall 2005 Motivation 2007 ~15 Petabytes/year LHC

Hugo HEPiX Fall 2005 Current Model CASTOR HSM RFIO DATA

Hugo HEPiX Fall 2005 IBM 3584 Library IBM 3592JA Tape Drive HP LT0-3STK SL GB 80 MB/sec 40 MB/sec 300 GB / 60 GB 1,448 carts 64 drives 117 carts 12 drives Devices Tested Future Generation Tape Drives >100 MB/s Testing in 2006

Hugo HEPiX Fall 2005 Test Infrastructure Tape Library Tape Drive Fiber Fiber Channel HBA Tape Server

Hugo HEPiX Fall 2005 Functionality Tests Go through the set of commands available on the SCSI standard Check returned information, timing, command acceptance SCSI 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

Hugo HEPiX Fall 2005 Functionality Tests fibre channel analyzer for verifying SCSI commands

Hugo HEPiX Fall 2005 Test Scenarios Linux tape driver and cernTapeTestUtil (interactive/command line mode)

Hugo HEPiX Fall 2005 Analysis of Results

Hugo HEPiX Fall 2005 Mechanical Tests IBM 3592: Over 125,000 mount/dismount cycles performed, no errors Test mechanical reliability of drive / media: some cartridges now mounted > 4000 times, no errors Random file reads on selected tapes and media: superseded by CASTOR operation in data challenges HP LTO-3: Over 125,000 mount/dismount cycles performed, no errors Test mechanical reliability of drive / media: some cartridges now mounted > 5000 times, no errors

Hugo HEPiX Fall 2005 Performance Tests - Use of native Linux Commands (mt/dd) for data transfers : read / write compression / no compression blocksize filesize position “labeled” files

Hugo HEPiX Fall 2005 Performance LTO-3 Data Transfer Rate Write no compression

Hugo HEPiX Fall 2005 Performance LTO-3 Data Transfer Rate Read no compression

Hugo HEPiX Fall 2005 LTO-3 Locate File Timing LTO-3 Locate Record Timing Performance Algorithm problem(?) seen older LTO-1 drives, just HP (? )

Hugo HEPiX Fall 2005 TapemarkData 0-? Bytes TapemarkHeader 1 80 Bytes Header 2 80 Bytes Header 3 80 Bytes Trailer 1 80 Bytes Trailer 2 80 Bytes Trailer 3 80 Bytes TapemarkSync ANSI Labels Headers Trailers Tapemark Sync Filename, block size, HSM version, time of writing … Number of blocks, non standard data … Flush buffer Special records on tape used by the drive, immediate bit =0/1

Hugo HEPiX Fall 2005 Labels vs Performance Minimum over head Maximum over head

Hugo HEPiX Fall 2005 Labels vs Performance HP-LTO3 IBM 3592JA

Hugo HEPiX Fall 2005 Labels vs Performance IBM 3592 small files

Hugo HEPiX Fall 2005 HSM Integration Functionality + Mechanical + Performance 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 OK Drive integration in HSM system

Hugo HEPiX Fall 2005 Operations IBM 3592/HP LT0-3: SNMP Agent : Error Counters Tape Alerts Drive and Media: number mounts/Loads/… IBM 3592: Statistical Analysis and Reporting System : bit 62: SARS Drive Relative Quality X'00' is unknown, best X'01' -> worst X'FF‘ bit 63 SARS Media Relative Quality X'00' is unknown, best X'01' -> worst X'FF' No Vendor: Perfect tool for monitoring all type of drives and for a large number of drives Request Sense

Hugo HEPiX Fall 2005 More Tests CASTOR HSM RFIO ?? $$ SAN