Veritas-bu

Re: [Veritas-bu] block size for restore

2009-02-19 07:34:12
Subject: Re: [Veritas-bu] block size for restore
From: Justin Piszcz <jpiszcz AT lucidpixels DOT com>
To: Jon Bousselot <jon-bousselot AT pacbell DOT net>
Date: Thu, 19 Feb 2009 06:56:00 -0500 (EST)
So you have the BUFFER size as 32k for LTO-1 and 64k or greater for LTO-4? 
sounds like you need one media server to have the buffer_size set for the 
LTO-1 drives and the other media server set to the other?

Some of the parameters:
NUMBER_DATA_BUFFERS
NUMBER_DATA_BUFFERS_RESTORE
SIZE_DATA_BUFFERS
SIZE_DATA_BUFFERS_DISK

First thing first, is the LTO-1 drive on its own media server where no 
other drives are attached (e.g., LTO-4?)


On Wed, 18 Feb 2009, Jon Bousselot wrote:

> Ooops, I didn't put enough details here.
> The LTO-1 drive/library is still attached to its original scsi
> controller on the host.  I added a new scsi card for the LTO-4 library.
>
> The task I need to accomplish is to duplicate selected images from the
> LTO1 media onto the LTO4 media, and then the LTO1 hardware goes away.
>
>
>
>> My understanding is that LTO4 drives are not backwards-read compatible with 
>> LTO1.  Only LTO2 & LTO3.
>>
>> LTO = Read 2 versions Back, Write 1 version Back.
>>
>> -Jonathan
>>
>> ________________________________
>>
>> From: veritas-bu-bounces AT mailman.eng.auburn DOT edu on behalf of Jon 
>> Bousselot
>> Sent: Wed 2/18/2009 2:26 PM
>> To: veritas-bu AT mailman.eng.auburn DOT edu
>> Subject: [Veritas-bu] block size for restore
>>
>>
>>
>> This one has me stumped.
>> Windows 2003 with all the latest patches.
>> Media written since 2003 shows up in the bpimagelist -L as having a
>> media block size of 65536.
>>
>> Upgrade to 6.5.3
>> SIZE_DATA_BUFFERS must now be 32768 because if it is anything else, I
>> get media write errors.
>>
>> When I try and restore data, the bptm logs show this
>>
>>
>> 2/17/2009 1:46:05 PM - Error bptm(pid=1996) tapemark or blank tape
>> encountered reading media header, drive index 1
>> 2/17/2009 1:46:06 PM - Error bptm(pid=1996) The tape device at index 1
>> has a maximum block size of 32768 bytes, a buffer size of 65536 cannot
>> be used
>> 2/17/2009 1:46:06 PM - Error bptm(pid=512) The following files/folders
>> were not restored:
>>
>>
>> I cannot read the old LTO-1 tapes.  They were stored at Iron Mountain
>> safely, and I tried more than three tapes from various years.
>> I verified the hotfix numbers for tape.sys and even tried updated tape
>> drive drivers with no success.
>>
>> NB docs (perf tuning guide) say the SIZE_DATA_BUFFERS is not even used
>> during a restore operation.
>> Is there a registry key that is forcing the drive to only accept 32k
>> blocks?
>> The LTO-4 drive is working just fine even at the 32k block size.
>>
>> -Jon Bousselot
>> _______________________________________________
>> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
>> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>>
>>
>>
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