Major Problem! i think

sajjan2 · July 15, 2003, 5:15am

Hi,
I relly could use your expert help.
We have an Sun Solaris machine here at my company and the person that is the administrator is at vacation.
The machined hangd and when we restarted it, it said.

"Disconnected tagged cmd(s) (1) timeout for target 1.0 "

What does this mean? can anyone help how to solve the problem
i have used UNIX machines some so i am not a total newbie.

Thanks a lot.

RTM · July 15, 2003, 9:31am

From Sunsolve:

Solaris[TM] sd driver taq queuing problems/sd_max_throttle

How does one fix SCSI disk tag queuing problem?

By setting sd_max_throttle, in /etc/system, to a lower value.

sd_max_throttle, a sd driver tunable parameter, determines the max
number of commands that can be queued up by sd to be submitted to the
HBA (Host Bus Adapter) driver. By default, sd_max_throttle is 256.
Since SCSI tag queuing, SCSI_OPTIONS_TAG (0x80), is enabled by default
in Solaris, when the disk controller is fully populated with targets
or having very fast disks (e.g., RAID devices), commands can be queued
up too fast (and reach the limit of 256) for sd driver to handle.
Once this condition is met, tagged command time-outs/retries or SCSI
transport failure messages often are displayed:

-> WARNING: /io-unit@f,e1200000/sbi@0,0/dma@0,81000/esp@0,80000 (esp1):
-> Disconnected tagged cmds (1) timeout for Target 1.0
-> WARNING: /io-unit@f,e1200000/sbi@0,0/dma@0,81000/esp@0,80000/sd@1,0 (sd16):
-> Error for command 'write' Error Level: Retryable
-> WARNING: /io-unit@f,e0200000/sbi@0,0/dma@0,81000/esp@0,80000/sd@3,0 (sd3):
-> SCSI transport failed: reason 'timeout': retrying command
-> WARNING: /io-unit@f,e0200000/sbi@0,0/dma@0,81000/esp@0,80000/sd@3,0 (sd3):
-> unix: SCSI transport failed: reason 'incomplete': retrying command

Setting sd_max_throttle to use a much smaller value, such as < 256, can fix
the problem.

To what value should sd_max_throttle be set? That depends on how many SCSI
targets are in the system. To have total queued commands < 100 can be a
workable rule (e.g., if there are 6 fast SCSI targets), and if sd_max_throttle
is set to be 16, the total queued commands can be 96. If tagged command
timeouts still are seen, then in /etc/system:

set sd:sd_max_throttle = 16

Suggest you go to Sunsolve and do a search as there is other information. If you have a contract with Sun (or if you are on warrenty), give them a call.

If not, post what OS/version, and the rest of the error message.

sajjan2 · July 16, 2003, 4:26am

I shut of the power, and started up tha machine again then
it worked properly. I guess i should insert the string in the file to prevent it from happening again, thank you.

/N