A new version of my "self-describing" command time-outs has been posted.  This is a major revision from the one posted last November.  I have a few issues to solve that I would appreciate help with.  The main one being how to sufficiently address or skirt the delay injected by the time in the queue.

My thoughts and experience are in the tape realm, and I don't have a good feel for disk or enclosure or MMC.  In the tape realm, reservations are often used to ensure that only one host is doing data I/O (or time intensive activities) at a time.  While multiple host may be talking to the drive, most are just polling to see if it is there or if it is available (i.e. doesn't have an active reservation).  In this scenario, the command time-outs as I have described them will solve a high percentage of the issues related to unknown command time-outs.  The delay injected by the queue (or the command(s) in the queue prior to this one) do not often have an effect on the host doing data I/O.
Anyway, I need to understand better the issues seen by the other device types.  I would also appreciate any suggestions.


2006/08/05 22:47:18

Your request to upload a file or files to the T10 site has been accepted.

Your PDF file will be posted at:

  http://www.t10.org/ftp/t10/document.05/05-284r2.pdf

Normally, the posting/archiving process takes about 30 minutes.

Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt@us.ibm.com
http://www-03.ibm.com/servers/storage/