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LT0-6 drive Block size modification in cell manager 9.08

Hi ,

Is there any way to modify block size of LT0 drives in data protector. by default it is 256kb

I want to increase it becuase Storeonce gateways are configured on 512KB and becuase of 512kb size , i cannot offload backup to tapes [MSL 6480] . ofcourse , reduce the size on storeonce gateways can be solution of this problem.

my environment- 9.08 cell manager + storeOnce 6500

thanks,

DPx

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Micro Focus Expert
Micro Focus Expert

Of course you can. Go into the drive advanced setting and change block size to max 1024 kB.

Regards,

 

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Micro Focus Expert
Micro Focus Expert

... and do not forget to reformat your tape before using them in the drive with the updated block size otherwise it will not work.

Regards,

 

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Hi ,

Many thanks for help.

I tried to change it but getting following message

 

[90:253]  Block Size setting of 1024KB is too big. Maximum allowed block size for
 this device type is 256KB.

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Micro Focus Expert
Micro Focus Expert

unless there is a new bug in DP 9.08 you should be able to set a block size of 1024kB. Can you please descrive when you receive the error message ?

It could also be caused by the card used to connect the LTO6 drive to the server. Which connection are using (Fiber Channel, SCSI cable, etc.) ? What is the Operating system of the server used to connect to the LTO drive (windows, linux , HP-UX, ...) ?Try also to add the variable OB2LIMITBLKSIZE=0 in omnirc file of the media server you use to connect to the LTO drive.

Regards,

 

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Hi  Dionisio,

many thanks for the help.

I'm getting message when i run offload copy job [data from storeonce to tape].

I'm using FC and tape is connected to physical server [RHEL 6.8]

OB2LIMITBLKSIZE=0 - i couldn't find in .omnirc file this parameter but i can add and try.

Thanks,

aman

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Hi, if the storeonce is 512kb block size then you need to configure the LTO6 devices in DP as 512kb too. Format the tapes then start a copy. This will work!

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@dpx wrote:

OB2LIMITBLKSIZE=0 - i couldn't find in .omnirc file this parameter but i can add and try.


You absolutely have to. For historic reasons (more related to shortcomings of HPUX and Solaris than Linux) the Unix MA refuses to use block sizes >256KiB by default, and this exact tunable will override that nonsense.

BTW, you don't have to reformat any tapes, that will happen automatically. The first time you write at the new (larger) block size, appending to not-yet-full tapes written at the old BS will fail with a warning, the tape will be ejected and DP continues on the next expired/unprotected/blank medium from the pool as it always does. And given it has to relabel that tape anyway, it uses the opportunity to relabel it at the new block size. All you see is a warning that this happened, so you can keep track of the progress. The new tape is then marked with a better write order number as well, so it will be used for writing from now on instead of the inappendable ones. The latter will bubble up in protection until they expire, and finally will be relabeled to the new BS as well when their time comes to be overwritten. The entire migration happens without any need to manually interfer - at least it did in countless migrations I performed from 64KiB to 256KiB and later 256KiB to 512KiB, on real tape and VTLs alike.

HTH,
Andre.

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