[Paranoia] Parallel ripping causes extreme slowdowns

[grarpamp]

On 12/13/19, Merlijn B.W. Wajer <merlijn at archive.org> wrote:
> how to approach fixing this problem.

> I have four drives happily ripping at good speeds, but -- the moment
> scsi read errors occur (or when cdrdao runs!), all the drives just slow
> down to a halt.

Some general notes on the hardware side...

The list probably doesn't have enough info about your
particular setup to help...

- CPU model
- Motherboard model
- OS and version
- Drive models
- Converter models

What you have plugged into which busses, exactly.

Are your motherboard, os, drives, etc all running
latest bios, firmware, code, etc.

Converters can be quite buggy, try to avoid them, really.
USB are often as quirky, and prone to cable / connector
issues from abuse and wear.

Yes try sata drives directly to motherboard sata ports.
Similarly, avoid multipliers, though extra pci sata port
jbod add in cards are usually ok. Old pata and scsi are
good too. Once things get properly tested and isolated
as needed.

Don't exceed the i/o capacity of any bus... that can
trigger streaming failures, renegotiation cycles, etc.
Check motherboard manual for bus layout and
bandwidth allocation, wikipedia for various speeds.

Your present setup might be seeing buggy cascading
bus or device resets / lockups, interrupt meltdowns or
some such. Some OS tools and settings will let you
watch or log that activity. It's separate from iops and bytes.

Some OS tools exist to force bus and device resets, reinit, rescans...
that might save you a hard reboot, but won't solve underlying problems.

Yes, settable modepages exist for sata, pata, scsi, usb drives...
that might let you fiddle with per device cache control, error
handling, etc beyond what the basic OS or ripper tools would.
Probably better to try different hardware than time trying that.

Start with a single drive connected that passes all your tests.
Add in other drives... one drive, change, and test at a time.
Keep notes.

Good luck :)