SN length and NULL medias

[sa0]

Hello,

2 simple questions,

Would it be easy to increase SERIAL length possibilities for libraries and tape to 30 chars ?
I don't know how to use NULL tapes, how to set it up ?

Thanks in advance,
Regards.

[Mark Harvey]

sa0 wrote

Would it be easy to increase SERIAL length possibilities for libraries and tape to 30 chars ?

Let me check on this one.. I'm not 100% sure if there are practical limitations in the SSC / SMC specs.

Is there a particular emulation combination you are looking at ?

Where practical, I do try and match the emulation documentation from the manufacturer.

sa0 wrote

I don't know how to use NULL tapes, how to set it up ?

Use the 'mktape' command and specify the NULL media type (or edit_tape to change an existing tape).

Note: The 'metadata' for each tape block is still written (512bytes per block).

I had to simulate a large tape (on limited disk space) one time - to test a value overflow in software GUI. But apart from that one time, I doubt this functionality has had much 'testing'. So I'd be interested to find how you found the 'feature'.
e.g. Why/what you are attempting, backup s/w and if it worked for you.

[sa0]

Hi Mark,

thank you so much for your answer.

(Sorry i also emailed to [e-mail] and some answers were in that message).

 

[sa0]

To be complete, here under is the message I sent through gmail :

----------------------------------------------------------------------------------------------------------------------------------------------
Would like to know if there is any chance you increase SN length size (both Library & Tape) to 30 chars ?
I use physical Quantum (Dxi and Scalar) in production and would like to be able to recreate exact same configuration with mhVTL on preprod environment but serial numbers are that long and at the moment I can’t fully simulate it ...

Also, could you please explain how to use NULL medias (as it should be possible according to mhvtl-1.5-0 changelog «   New media type 'NULL' for performance testing » ) ?
My goal is to simulate real production backup plan but no write at all
----------------------------------------------------------------------------------------------------------------------------------------------

[Mark Harvey]

Can I please ask for the output of the following commands (run against a real Quantum tape library)..

Their documentation is a little unclear on how it handles ‘larger’ serial numbers.

e.g.

VPD page 80 specifies a field of 24 char but the first 8 chars are used for the Vendor-ID (QUANTUM) - leaving 16 chars.

QUANTUM123456789 or QUANTUM123456789_LL1

However, page 83 also specifies a field of 24 bytes, but without the Vendor-ID prefix..

I’m curious about the format for serial numbers which exceed 16 characters..

 Where /dev/sgXX is the device of the robotic changer:

# sg_inq -v -p 80 /dev/sgXX

# sg_inq -v -p 83 /dev/sgXX

FWIW: The Quantum Scalar_6 SCSI reference reflects a max serial number length of 24 characters. While the code can be modified to handle any practical length, application software will most likely fail if/when they query the information and (potentially) are not coded to handle lengths which exceed the documentation.

Re: tape devices:

What type of tape drives do you have in your library (or which emulation within the mhVTL are you planning on using) ?

I’ve just confirmed with the IBM LTO8 and it has a limit of 10 characters (same across the entire LTO range).

Perhaps the above ‘sg_inq’ commands against real hardware will help me identify “real world” vs “what is documented”.

Cheers

On 22 Nov 2018, at 8:15 pm, sa0 [via mhVTL - A Linux Virtual Tape Library] <[hidden email]> wrote:

To be complete, here under is the message I sent through gmail :

----------------------------------------------------------------------------------------------------------------------------------------------
Would like to know if there is any chance you increase SN length size (both Library & Tape) to 30 chars ?
I use physical Quantum (Dxi and Scalar) in production and would like to be able to recreate exact same configuration with mhVTL on preprod environment but serial numbers are that long and at the moment I can’t fully simulate it ...

Also, could you please explain how to use NULL medias (as it should be possible according to mhvtl-1.5-0 changelog «   New media type 'NULL' for performance testing » ) ?
My goal is to simulate real production backup plan but no write at all
----------------------------------------------------------------------------------------------------------------------------------------------

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NAML

[sa0]

Hello Mark,

Here in real world  :

VTL Quantum DXi 6700 emulates a Scalar i2000

# sg_inq -v -p 0x80 /dev/sg25

VPD INQUIRY: Unit serial number page
    inquiry cdb: 12 01 80 00 fc 00 
    inquiry: pass-through requested 252 bytes but got 28 bytes
  Unit serial number: VL005CX1149BVE01092

# sg_inq -v -p 0x83 /dev/sg25

VPD INQUIRY: Device Identification page
    inquiry cdb: 12 01 83 00 fc 00 
    inquiry: pass-through requested 252 bytes but got 91 bytes
  Designation descriptor number 1, descriptor length: 47
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: ADIC    
      vendor specific: Scalar i2000    VL005CX1149BVE01092
  Designation descriptor number 2, descriptor length: 8
    designator_type: vendor specific [0x0],  code_set: Binary
    associated with the addressed logical unit
      vendor specific:
        00 00 00 00
  Designation descriptor number 3, descriptor length: 12
    designator_type: EUI-64 based,  code_set: Binary
    associated with the target port
      EUI-64 based 8 byte identifier
      IEEE Company_id: 0x500e09
      Vendor Specific Extension Identifier: 0xe200b8a111
      [0x500e09e200b8a111]
  Designation descriptor number 4, descriptor length: 12
    designator_type: NAA,  code_set: Binary
    associated with the target port
      NAA 5, IEEE Company_id: 0xe09e
      Vendor Specific Identifier: 0x200b8a111
      [0x500e09e200b8a111]
  Designation descriptor number 5, descriptor length: 8
    designator_type: Relative target port,  code_set: Binary
    associated with the target port
      Relative target port: 0x1

Tape devices I usually emulate are HP or IBM LTO 3, 4 or 5

Here is an example of the lsscsi listing

# lsscsi -g
[0:2:0:0]    disk    IBM      ServeRAID M5110e 3.34  /dev/sda   /dev/sg0 
[0:2:1:0]    disk    IBM      ServeRAID M5110e 3.34  /dev/sdb   /dev/sg1 
[3:0:0:0]    cd/dvd  IBM SATA  DEVICE 81Y3672  SA81  /dev/sr0   /dev/sg2 
[8:0:1:0]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st23  /dev/sg30
[8:0:1:1]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st24  /dev/sg31
[8:0:1:2]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st25  /dev/sg32
[8:0:1:3]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st26  /dev/sg33
[8:0:2:0]    mediumx ADIC     Scalar i2000     120A  /dev/sch2  /dev/sg25
[8:0:2:1]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st19  /dev/sg26
[8:0:2:2]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st20  /dev/sg27
[8:0:2:3]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st21  /dev/sg28
[8:0:2:4]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st22  /dev/sg29
[8:0:3:0]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st8   /dev/sg14
[8:0:3:1]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st9   /dev/sg15
[8:0:3:2]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st10  /dev/sg16
[8:0:3:3]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st11  /dev/sg17
[8:0:4:0]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st4   /dev/sg10
[8:0:4:1]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st5   /dev/sg11
[8:0:4:2]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st6   /dev/sg12
[8:0:4:3]    tape    HP       Ultrium 5-SCSI   I30Z  /dev/st7   /dev/sg13
[10:0:1:0]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st27  /dev/sg34
[10:0:1:1]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st28  /dev/sg35
[10:0:1:2]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st29  /dev/sg36
[10:0:1:3]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st30  /dev/sg37
[10:0:2:0]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st15  /dev/sg21
[10:0:2:1]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st16  /dev/sg22
[10:0:2:2]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st17  /dev/sg23
[10:0:2:3]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st18  /dev/sg24
[10:0:3:0]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st12  /dev/sg18
[10:0:3:1]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st13  /dev/sg19
[10:0:3:2]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st14  /dev/sg20
[10:0:4:0]   mediumx ADIC     Scalar i2000     120A  /dev/sch1  /dev/sg6 
[10:0:4:1]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st1   /dev/sg7 
[10:0:4:2]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st2   /dev/sg8 
[10:0:4:3]   tape    HP       Ultrium 5-SCSI   I30Z  /dev/st3   /dev/sg9

And VPD inquiry on one of these tape :

# sg_inq -v -p 0x80 /dev/sg9

VPD INQUIRY: Unit serial number page
    inquiry cdb: 12 01 80 00 fc 00 
    inquiry: pass-through requested 252 bytes but got 23 bytes
  Unit serial number: VD086CX1149BVE01092

# sg_inq -v -p 0x83 /dev/sg9

VPD INQUIRY: Device Identification page
    inquiry cdb: 12 01 83 00 fc 00 
    inquiry: pass-through requested 252 bytes but got 91 bytes
  Designation descriptor number 1, descriptor length: 47
    designator_type: T10 vendor identification,  code_set: ASCII
    associated with the addressed logical unit
      vendor id: HP      
      vendor specific: Ultrium 5-SCSI  VD086CX1149BVE01092
  Designation descriptor number 2, descriptor length: 8
    designator_type: vendor specific [0x0],  code_set: Binary
    associated with the addressed logical unit
      vendor specific:
        00 00 00 00
  Designation descriptor number 3, descriptor length: 12
    designator_type: EUI-64 based,  code_set: Binary
    associated with the target port
      EUI-64 based 8 byte identifier
      IEEE Company_id: 0x500e09
      Vendor Specific Extension Identifier: 0xe200b8a113
      [0x500e09e200b8a113]
  Designation descriptor number 4, descriptor length: 12
    designator_type: NAA,  code_set: Binary
    associated with the target port
      NAA 5, IEEE Company_id: 0xe09e
      Vendor Specific Identifier: 0x200b8a113
      [0x500e09e200b8a113]
  Designation descriptor number 5, descriptor length: 8
    designator_type: Relative target port,  code_set: Binary
    associated with the target port
      Relative target port: 0x3

FYI, backup software we use is "Time Navigator" from Atempo, I can tell you mhVTL is validated with ...

One last thing, what about NULL medias ?
My aim is to run backup plans as in real life but no storage consuming ...

[sa0]

Hello Mark,

Forget about the NULL medias (at least for me) I've managed a way to get what I wanted.

What about SN length, do the inquiries I supplied suits your needs ?

Best regards...

[sa0]

Hi Mark,

Happy new year to you and all your mates,

Any news concerning the ability to increase SN length (lib and tapes) ?