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Subject: Re: getting a disk structure given a device name
To: "Pokala, Ravi" <rpokala@panasas.com>,
 "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
References: <D1DF8804.13F03F%rpokala@panasas.com>
From: Julian Elischer <julian@freebsd.org>
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Date: Fri, 31 Jul 2015 13:56:57 +0800
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On 7/30/15 11:22 PM, Pokala, Ravi wrote:
>> Date: Wed, 29 Jul 2015 23:31:03 +0000
>> From: Raviprakash Darbha <rdarbha@juniper.net>
>> To: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>
>> Cc: Steve Kiernan <stevek@juniper.net>, Simon Gerraty
>> 	<sjg@juniper.net>
>> Subject: getting a disk structure given a device name
>> Message-ID: <F8ED1BDC-D8DA-458B-A652-B125183F27CB@juniper.net>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Hello All
>>
>> I am trying to write a filter driver for the ata block on freebsd 6.2 to
>> simulate failed reads and writes.

6.2!!!??
I thought I was in trouble being stuck on 8.0!

> We originally did something like that at Panasas, but by hacking ata(4)
> and ad(4) directly. :-P Later on, we created a GEOM class to do error
> injection. Currently, I prefer using the WRITE_UNCORRECTABLE48 command, to
> tell the drive to actually return errors on subsequent reads. That has the
> benefit of being indistinguishable from an actual read failure - the drive
> spends the time to do error recovery, and sends the actual error code back.
>
> -Ravi
>
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