On 14.04.2010 09:33, Matthias Pfützner wrote: > You (Svein Skogen) wrote: >>> Check: >>> >>> http://storagemojo.com/2007/09/19/cerns-data-corruption-research/ >> >> Which is another worthless document, without any info on what >> controllers they actually tested with. >> >> I too can make claim about corruption and data loss. But without >> pointing the finger to what was actually tested, that's just a claim, >> nothing more. >> >> //Svein > > What's it, your after? That study is more than 2 years old now, and the > RAID-controllers, that didn't work, probably will have updated their FWs by > now.
Ahh, so first you use the papers to prove how superior ZFS is to raidcontrollers for your data. Then, when asked to provide more data than this claim, the study is too old and the problems are fixed? Which is it, is the study still valid, or is it deprecated? > And: The Authors are listed, so, go ask them, if you really are interested in > those details. > > More importantly is the fact, that bit-errors DO happen, and as I stated > earlier, with the average failure rate and storage size of today it's close to > 100% certainty, that if you have more than 128 TB of data, you have an > error. That's a simple derivative from the infos, available from the > manufactures themselfes: > > For example, for the Seagate ST31000640SS (1 TB SATA): > > AFR: 0,73% > Nonrecoverable Read Errors per Bits Read: 1 sector per 10E15 > Error Control/Correction (ECC): 10 bit > >>From AFR: If you have 200 disks, 1.46 die per year. > ECC: If you have 1024 errors, one will NOT be detected > After that: 1 sector per 10E15 Bit ~= 128 TB is defect > More precisely: 10E15 = (10E3)E5 = 1024E5 Bit = 1024 Terabit = 116.4 > Terabyte => There's a defect sector every 116.4 Terabit. > > These are the DOCUMENTED ERROR RATES of standard consumer disks! Take > enterprise disks, and it's around 1 sector per 10E16 bit and an AFR of 0.55% > (Seagate Savvio 15K.2 ST9146752SS). So, not as bad as above, but still there > are documented possibilities of errors! > > And, therefore, it's now a necessity to do error checking at every level! Which is why such error-checking should be done by proper raid-controllers (and it is, btw). Read that properly. I did not say that it should _ONLY_ be done in the raid controller. Doing it on fs-level as well only adds to the protection. //Svein -- --------+-------------------+------------------------------- /"\ |Svein Skogen | [email protected] \ / |Solberg Østli 9 | PGP Key: 0xE5E76831 X |2020 Skedsmokorset | [email protected] / \ |Norway | PGP Key: 0xCE96CE13 | | [email protected] ascii | | PGP Key: 0x58CD33B6 ribbon |System Admin | [email protected] Campaign|stillbilde.net | PGP Key: 0x22D494A4 +-------------------+------------------------------- |msn messenger: | Mobile Phone: +47 907 03 575 |[email protected] | RIPE handle: SS16503-RIPE --------+-------------------+------------------------------- If you really are in a hurry, mail me at [email protected] This mailbox goes directly to my cellphone and is checked even when I'm not in front of my computer. ------------------------------------------------------------ Picture Gallery: https://gallery.stillbilde.net/v/svein/ ------------------------------------------------------------
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