Date: Sun, 9 Mar 2008 13:45:22 +0100 From: Ben Stuyts <ben@altesco.nl> To: duncan.young@pobox.com Cc: freebsd-current@freebsd.org Subject: Re: write cache on usb disks and zfs Message-ID: <990680CB-A797-41C2-BDF0-E4968DFBDB94@altesco.nl> In-Reply-To: <200803091525.27311.duncan.young@pobox.com> References: <200803091525.27311.duncan.young@pobox.com>
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Hi, On 9 Mar 2008, at 06:25, Duncan Young wrote: > I am trying to use the USB drives for backup and would like to use > zfs on > them, but the problem I have is with the cache disabled, I get lots of > > kernel: (da2:umass-sim0:0:0:0): SYNCHRONIZE CACHE. CDB: 35 0 0 0 0 0 > 0 0 0 0 > kernel: (da2:umass-sim0:0:0:0): CAM Status: SCSI Status Error > kernel: (da2:umass-sim0:0:0:0): SCSI Status: Check Condition > kernel: (da2:umass-sim0:0:0:0): ILLEGAL REQUEST asc:20,0 > kernel: (da2:umass-sim0:0:0:0): Invalid command operation code > kernel: (da2:umass-sim0:0:0:0): Unretryable error > > errors in /var/log/messages. > > I am assuming that the error messages are harmless, but it would be > nice for > zfs to pay attention and not continually issue the commands. Is > there a way > to do this? I had exactly the same problem (on 7-stable) and have added a quirk for this particular drive to scsi_da.c. In my case the drive became unresponsive for a few seconds, so the transfer rate was very low. Works fine so far with the quirk. I have filed a PR where you can see my changes: http://www.freebsd.org/cgi/query-pr.cgi?pr=121474 Ben
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