On Tue, 1 Dec 2020, Tim Woodall via GLLUG wrote:
I burn backups to blu-ray about once per month.
Commandline is:
growisofs -dvd-compat -speed=1 -Z /dev/cdrom=$UDFIMAGE
Mostly this works fine: I get messages like:
2288910336/24756879360 ( 9.2%) @0.9x, remaining 96:21 RBU 100.0% UBU 96.9%
2302017536/24756879360 ( 9.3%) @0.9x, remaining 96:24 RBU 100.0% UBU 96.9%
2315321344/24756879360 ( 9.4%) @0.9x, remaining 96:16 RBU 100.0% UBU 96.9%
2328100864/24756879360 ( 9.4%) @0.9x, remaining 96:10 RBU 100.0% UBU 96.9%
2340225024/24756879360 ( 9.5%) @0.8x, remaining 96:16 RBU 100.0% UBU 96.9%
2353135616/24756879360 ( 9.5%) @0.9x, remaining 96:09 RBU 100.0% UBU 96.9%
...
However, it's started burning at double speed @2.1x sometimes. Sometimes
the burn completes like that, but doing an md5sum on the image (which I
always do once I've burned the disk) shows that there are definitely
some errors although the disk will mount ok.
And other times the burn fails part way through.
Does anyone know why it's ignoring my -speed=1 setting?
From the manpage:
Keep in mind that N essentially denotes speed closest to N*1385KBps in
DVD or N*4496KBps in Blu-ray Disc case
Based on the snippet above - roughly 105 minutes to burn this disk.
24756879360/4496000/0.9 = 101 minutes.
So the maths looks correct and I don't know why it's sometimes burning
at 2.1x.
And as soon as I sent the above the burn actually failed:
9682092032/24756879360 (39.1%) @0.9x, remaining 64:22 RBU 100.0% UBU 96.9%
:-( unable to WRITE@LBA=4829a0h: Input/output error
:-( write failed: Input/output error
/dev/cdrom: flushing cache
:-( unable to FLUSH CACHE: Input/output error
:-( unable to SYNCHRONOUS FLUSH CACHE: Input/output error
That's the first time I've had a 0.9 speed burn fail :-(
Tim.
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