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MSL5026 with SDLT 320 drives unable to write 64 bit block size

Matt_276
Occasional Advisor

MSL5026 with SDLT 320 drives unable to write 64 bit block size

I have recently installed Commvault 5.9 backup software on Windows 2003.

When backing up by default Commvault attempts to write in 64 bit blocks, this causes errors within the software, reporting a 'Hardware Error'. Changing the default write size to 32 bit blocks resolves the problem.

The firmware version of the library is v4.23 and the SDLT 320 tape drives is v.82.

Questions:
1. Has anyone come accross this problem before? Is it likely to be hardware or software related?

2. Whit kind of performance hit could be expected writing at 32 bit blocks instead of 64?

Thanks in advance for your help
3 REPLIES

Re: MSL5026 with SDLT 320 drives unable to write 64 bit block size

Hi Matt,

Open the registy and search for ..\Parameters\Device\MaximumSGList
change this value to 67 Decimal and reboot this
server. This should help.
There ist not so much performance gain 32 to 64K. But about 5..10% from 32K to 256K

Best Regards
Roland

Re: MSL5026 with SDLT 320 drives unable to write 64 bit block size

Hi Matt,

i forgot some explanationin my last repl.
This comes from the HP Dataprotector Admin Guide

Regards
Roland
Marino Meloni_1
Honored Contributor

Re: MSL5026 with SDLT 320 drives unable to write 64 bit block size

did it occur an brand new tapes, or only on already used tapes?
When the tape is used the first time, some informations should indicate the block size used on that tape, obviously, trying to append at a different block size could cause problems.
Also W2K3 have inserted in his SP1 an updated Tape.sys version that limit block size to 64 KByte on system with 64 bits for compatibility reason with system 32Bits, I'm not sure is something similar occured also on the 32 but version.
keep in mind these info and check if some appy to your case
marino