Date: Wed, 16 Jul 2008 11:08:58 +1000 From: Andrew Snow <andrew@modulus.org> To: freebsd-stable@freebsd.org Subject: Re: taskqueue timeout Message-ID: <487D4A2A.9010508@modulus.org> In-Reply-To: <200807151711.m6FHBgVO007481@apollo.backplane.com> References: <487CCD46.8080506@ibctech.ca> <200807151711.m6FHBgVO007481@apollo.backplane.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Matthew Dillon wrote: > Try that first. If it helps then it is a known issue. Basically > a combination of the on-disk write cache and possible ECC corrections, > remappings, or excessive remapped sectors can cause the drive to take > much longer then normal to complete a request. The default 5-second > timeout is insufficient. From Western Digital's line of "enterprise" drives: "RAID-specific time-limited error recovery (TLER) - Pioneered by WD, this feature prevents drive fallout caused by the extended hard drive error-recovery processes common to desktop drives." Western Digital's information sheet on TLER states that they found most RAID controllers will wait 8 seconds for a disk to respond before dropping it from the RAID set. Consequently they changed their "enterprise" drives to try reading a bad sector for only 7 seconds before returning an error. Therefore I think the FreeBSD timeout should also be set to 8 seconds instead of 5 seconds. Desktop-targetted drives will not respond for over 10 seconds, up to minutes, so its not worth setting the FreeBSD timeout any higher. More info: http://www.wdc.com/en/library/sata/2579-001098.pdf http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery - Andrew
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?487D4A2A.9010508>