Date: Fri, 7 Nov 2008 00:36:26 -0800 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: Artem Belevich <fbsdlist@src.cx> Cc: votdev@gmx.de, freebsd-hardware@freebsd.org, freebsd-stable@freebsd.org, sos@freebsd.org Subject: Re: Western Digital hard disks and ATA timeouts Message-ID: <20081107083626.GA1583@icarus.home.lan> In-Reply-To: <ed91d4a80811070008t50bf96bdhdd18fb6a830f2ec2@mail.gmail.com> References: <20081107071752.GA5842@icarus.home.lan> <ed91d4a80811070008t50bf96bdhdd18fb6a830f2ec2@mail.gmail.com>
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On Fri, Nov 07, 2008 at 12:08:01AM -0800, Artem Belevich wrote: > > Note that Western Digital's "RAID edition" drives claim to take up to 7 > > seconds to reallocate sectors, using something they call TLER, which > > force-limits the amount of time the drive can spend reallocating. TLER > > cannot be disabled: > > TLER can be enabled/disabled on recent WD drives (SE16/RE2/GP). SE16/GP > come with TLER off, RE2 with TLER on. Google WDTLER utility. > It can apparently be obtained from WD by asking them nicely. > Or, yet again, google is your friend. Here's one example - > http://www.hardforum.com/archive/index.php/t-1191548.html Thanks for the information. Nice to know one of their FAQ entries is false. Also, note that "SE16/RE2/GP" is not specific enough; I have SE16 drives from 2005, and I highly doubt those have TLER capability due to their age. Also, there's a Wikipedia article on this whole fiasco. http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery It also appears Samsung drives have a similar feature called CCTL, which uses a value of 7 or 8 seconds: http://www.samsung.com/global/business/hdd/learningresource/whitepapers/LearningResource_CCTL.html But regardless of TLER being toggleable, FreeBSD's ATA command timeout of 5 seconds is too aggressive, and should be increased. Likewise, the value should be a sysctl, so those who do want such aggressive values can use it at the community's -- or their own -- behest. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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