From mboxrd@z Thu Jan 1 00:00:00 1970 From: lm@bitmover.com (Larry McVoy) Date: Fri, 22 Jan 2010 07:38:25 -0800 Subject: [TUHS] Irwin 285 In-Reply-To: <20100122111557.11f08ebc.jkunz@unixag-kl.fh-kl.de> References: <20100121195619.GE25687@freebie.xs4all.nl> <20100121195818.GF9956@bitmover.com> <20100121200034.GG25687@freebie.xs4all.nl> <20100121201125.GG9956@bitmover.com> <46b366131001211226v1a133901mefa41b3258a5b173@mail.gmail.com> <20100121204157.GI25687@freebie.xs4all.nl> <20100121204429.GH9956@bitmover.com> <20100122101424.50c0e716.jkunz@unixag-kl.fh-kl.de> <20100122093409.GB34725@freebie.xs4all.nl> <20100122111557.11f08ebc.jkunz@unixag-kl.fh-kl.de> Message-ID: <20100122153825.GA22757@bitmover.com> On Fri, Jan 22, 2010 at 11:15:57AM +0100, Jochen Kunz wrote: > On Fri, 22 Jan 2010 10:34:09 +0100 > Wilko Bulte wrote: > > > recoverable read error rate I presume. > No. NON-recoverable read error rate: 1 per 10^14 bits. > > And this is for light desktop use. Heavy IO on the disk may increase > failure rate. At least this is written in the technical data sheet of > the drive. WD drives are not that much better: 1 per 10^15 bits. You guys are funny. I've been doing backups for at least 15 years and I can tell you story after story about tape failures that happened to me personally (anyone remember the lovely exabyte 8200, "fondly" remembered as the write-only device?). On the other hand, disks work pretty well and when they fail, they fail in little chunks and you can almost always get the rest of the data. For the data I really care about, our digital photo collection, it's all stored in BitKeeper's so-called binary asset management (BAM). All the data is CRC-ed, it's all replicated, and if anything goes bad the bad data can easily be replaced from any of the other (populated) replicas. I periodically run "bk bam check" which goes through all the data and checks the crc's and have yet to see an error. Been doing that for years. Tape. Bah. You can keep it, I'm OK with disk. -- --- Larry McVoy lm at bitmover.com http://www.bitkeeper.com _______________________________________________ TUHS mailing list TUHS at minnie.tuhs.org https://minnie.tuhs.org/mailman/listinfo/tuhs