[illumos-Developer] Changing sd_io_time to 8?

[Richard Elling]

On May 5, 2011, at 3:15 AM, Joerg Schilling wrote:

> "Garrett D'Amore" <garrett at nexenta.com> wrote:
> 
>> I think we can be smarter here too.
>> 
>> CDROMS need a longer recovery time.
>> 
>> Disks on Parallel SCSI might need longer.
>> 
>> Disks on fibre, SAS, and SATA, should all respond within a narrow window
>> of time unless something is seriously amiss.
> 
> There is no difference between Parallel SCSI and other SCSI transports besides 
> just the transport itself.
> 
> A hard-disk that is just booting after a power on or reset and that has read 
> problems in one of the copies for the firmware sectors or in one of the copies
> for the defect list sectors may take a _long_ time too to recover and it is of 
> course worth to wait at least a minute in such a case.
> 
> If you really like to speed things up, start thinking about a way to reduce the 
> number of driver level _retries_ in case of problems if the related disk is 
> part of a RAID-Z2 and the dataa could be recovered otherwise.

More retries, shorter timeouts, fewer resets is the goal.
 -- richard