Moore, Eric wrote:
QUEUE_FULL and SAM_STAT_TASK_SET_FULL are not errors.
I consider them errors in the same way that ENOMEM or ENOBUFS (or even
EAGAIN) are errors. "There is a shortage of resources and the command
could not be completed, please try again later."
Also, the behaviour has changed from 2.6.10 with the 3.01.18 fusion
driver, to 2.6.14 with the 3.02.57 fusion driver.
With 2.6.10 our user app never saw SAM_STAT_TASK_SET_FULL. I suspect it
is due to the fact that it's using a queue size of 7, while in 2.6.14
it's using a queue size of 32 or 64.
Which kernel version is behaving properly?
I've asked seagate what the queue size should be for that hardware, but
haven't heard back yet.
SAM_STAT_TASK_SET_FULL returned for the target that handle the number of
commands, and QUEUE_FULL returned from hba firmware meaning its can't
handle the number of commands. Translated, the commands are retried by
scsiml. I probably should be calling scsi_track_queue_full which
would be throttling the command back, however I'm not sure whether it
matters.
We have a userspace app calling ioctl(...SG_IO...) on /dev/sdX and
occasionally getting a status of SAM_STAT_TASK_SET_FULL. I may be
misreading the code, but it doesn't appear that the midlayer is retrying
these commands.
If the queue length in 2.6.14 is correct then how do I handle that
status code? Maybe delay a bit then retry a few times? How much delay?
How many retries?
Chris
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