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Testing High Performance Tape Drives . HEPiX FALL 2005 Data Services Section. Motivation . LHC. 2007. ~15 Petabytes/year . Current Model. RFIO. DATA. DATA. DATA. DATA. CASTOR HSM. DATA. DATA. Devices Tested. IBM 3592JA Tape Drive. IBM 3584 Library. +. +.

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Testing high performance tape drives l.jpg

Testing High Performance Tape Drives

HEPiX FALL 2005

Data Services Section


Motivation l.jpg

Motivation

LHC

2007

~15 Petabytes/year


Slide3 l.jpg

Current Model

RFIO

DATA

DATA

DATA

DATA

CASTOR

HSM

DATA

DATA


Slide4 l.jpg

Devices Tested

IBM 3592JA Tape Drive

IBM 3584 Library

+

+

Future Generation Tape Drives >100 MB/s

Testing in 2006

300 GB / 60 GB

40 MB/sec

117 carts

12 drives

STK SL8500

HP LT0-3

+

+

400 GB

1,448 carts

80 MB/sec

64 drives


Test infrastructure l.jpg

Tape Server

Tape Library

Test Infrastructure

Fiber

Fiber Channel HBA

Tape Drive


Functionality tests l.jpg

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





Mechanical tests l.jpg

Mechanical Tests line mode)

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Random file reads on selected tapes and media: superseded by CASTOR operation in data challenges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


Performance tests l.jpg

Performance Tests line mode)

  • Use of native Linux Commands (mt/dd) for data transfers :

    • read / write

    • compression / no compression

    • blocksize

    • filesize

    • position “labeled” files


Performance l.jpg

LTO-3 Data Transfer Rate line mode)

Write no compression

Performance


Performance13 l.jpg

LTO-3 Data Transfer Rate line mode)

Read no compression

Performance


Performance14 l.jpg

LTO-3 Locate File Timing line mode)

Algorithm problem(?) seen older

LTO-1 drives, just HP (? )

LTO-3 Locate Record Timing

Performance


Slide15 l.jpg

80 Bytes line mode)

0-? Bytes

80 Bytes

80 Bytes

80 Bytes

80 Bytes

80 Bytes

Trailer 2

Trailer 1

Header 3

Trailer 3

Header 1

Data

Header 2

Tapemark

Tapemark

Tapemark

Sync

ANSI Labels

Headers

Filename, block size, HSM version, time of writing …

Number of blocks, non standard data …

Trailers

Tapemark

Special records on tape used by the drive, immediate bit =0/1

Sync

Flush buffer


Slide16 l.jpg

Labels vs Performance line mode)

Minimum

over head

Maximum

over head


Slide17 l.jpg

Labels vs Performance line mode)

HP-LTO3

IBM 3592JA


Slide18 l.jpg

Labels vs Performance line mode)

IBM 3592

small files


Hsm integration l.jpg

HSM Integration line mode)

OK

Drive integration in HSM system

  • 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

Functionality + Mechanical + Performance

Castor Production


Operations l.jpg

IBM 3592/HP LT0-3: line mode)

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

Operations

Request Sense


Slide21 l.jpg

SAN line mode)

More Tests

RFIO

CASTOR

HSM

$$

??


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