Re: [parisc-linux] Hanging with kernels >= 2.4.22

[Riccardo <rollei@tiscalinet.it>]

Carlos O'Donell wrote:
> 
> > Thanks! Changing NCR_700_MAX_TAGS to 1 in drivers/scsi/53c700.h did the
> > trick. Will I now have poor disk performance? If so, might I get away
> > with setting it to something higher, like 2 or 4, maybe?
> 
> I could never run IO stably at anything higher than 1. The drives don't
> seem to handle it properly, the error recovery mechanisms seem less
> than perfect, and the box just hangs.
It really depends on the drive. I have a Fujitsu Enterprise and it has a
specified tag queue of 128 commands. So if something fails, it is the
driver or HP's hardware.

I have a 715 scorpio and when I used ext2 or reiser with a tag queue of
16 I had very frequent freezes up to a point were the system wouldn't
even mount the partition.

There was a discussion that hp set it to 2 for workstations and to 8 for
servers. I have set it right now to 8 (since mavbe the NCR 7100 I have
doesn't even support more) and I use XFS instead of reiser. I had no
more problems...

I would set the tag queue as default to 8 and not to 16, to stay on the
safe side. Couldn't it be made configurable from the kernel
configuration menu?


What I notivced that some drives seem to be incompatible. I had 2 hard
disks that worked together (an original quantum divre rebranded HP and
an IBM disk). Since my ibm disk died I substitued it with the Fujitsu,
used a new Filesystem and a newer kernel. There was no way to see both
disks when linux booted. I had to remove the original HP disk and
substitute it (a nuisance, since it contained the home directories).
Attaching each time only one of the two disks recognized the correct
disk respectively but both disk weren't. Another disk had no problem.

-Riccardo