Timeline for RAID-5: Two disks failed simultaneously?
Current License: CC BY-SA 3.0
24 events
| when toggle format | what | by | license | comment | |
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| Nov 22, 2018 at 2:22 | vote | accept | Mike Furlender | ||
| Jul 25, 2014 at 17:35 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 24, 2014 at 19:39 | comment | added | Rob Moir | Shame this got down votes - I agree that it doesn't deserve downvotes because it's a sincere attempt to help, but it's a hail-mary last gasp desperate attempt to salvage something from the trainwreck, not a (with all respect to Peter) 'proper' solution to RAID 5 failures. | |
| Jul 24, 2014 at 18:06 | comment | added | TomTom | @queueoverflow So true - 1990. Today not. Same manufacturer compatible line is more like it. | |
| Jul 24, 2014 at 15:45 | comment | added | War | potentially, assuming all the disks still spin ok this is possible, and worst case the loss could be 0 ... its tough but can be done. takes hours though ... more likely days on big drives. | |
| Jul 24, 2014 at 14:02 | comment | added | Martin Ueding | @MikeFurlender I think hardware is faster, but proprietary and therefore brittle as you need to get the exact same controller in case it fails. Software RAID is independent of the hardware. See btrfs and zfs. | |
| Jul 24, 2014 at 9:22 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 24, 2014 at 7:44 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 23, 2014 at 17:43 | comment | added | Arnaud Meuret | "You could easily make a sector-level copy of a block copy tool" Is this really what you meant to write? | |
| Jul 23, 2014 at 16:57 | comment | added | Vality | @JamesRyan I agree that it will cause some later problems and I even agree that there are underlying issues here. However it does offer a valid solution on how to get some functionality back and as the OP was talking about data recovery experts I can only assume they do not have backups to get their data back otherwise. In the end, this solution would only be part one of a fix, once this method had got the system booted again, you would probably want to transfer the filesystem to 5 new disks and then importantly back it up. | |
| Jul 23, 2014 at 16:25 | comment | added | JamesRyan | @Vality it doesn't try to solve the mess, it extends his problems. A raid5 with corrupted blocks burnt in gives no end of pain as it will pass integrity checks but regularly degrade. Also he would have no idea which data is corrupt. If it was as easy as fixing a block that would be the standard solution. | |
| Jul 23, 2014 at 16:02 | comment | added | Mike Furlender | Wouldn't a hardware RAID controller perform better than a software one? | |
| Jul 23, 2014 at 14:54 | comment | added | Vality | Shame this got down votes, it actually tries to help the OP fix the mess unlike some of the others. +1 | |
| Jul 23, 2014 at 14:26 | comment | added | peterh | @BigHomie Ok, maybe. No prob, I hope. | |
| Jul 23, 2014 at 14:25 | comment | added | MDMoore313 | @PeterHorvath I think we're saying the same thing, I just misunderstood your translation. | |
| Jul 23, 2014 at 14:12 | comment | added | MDMoore313 | Exactly, copying a sector block by block is fine, copying blocks at the sector level will likely server no usefulness. | |
| Jul 23, 2014 at 14:11 | comment | added | peterh | @Basil Maybe you don't understood enough well what is a block or sector-level copy. You suggested him a total data loss, although his system was able to survive with a single block error. | |
| Jul 23, 2014 at 14:08 | comment | added | Basil | Whatever caused it to freeze his rebuild would still be in there, potentially. Sometimes bad sectors can't be recovered with a block copy. That said, to get this server back online, the professional solution is to recover from a recent backup and not spend time trying to do low-level data recovery which may not even work. | |
| Jul 23, 2014 at 14:06 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 23, 2014 at 14:05 | comment | added | peterh | @BigHomie There is a legion for that. Google for "sector level cloning of disks with bad block", or such. I personally developed a simple C tool for that, but it could be developed in bash as well. Sorcery? No, it is not sorcery, I am simply thinking a professional sysadmin shouldn't stop on a single bad block... | |
| Jul 23, 2014 at 14:02 | comment | added | MDMoore313 |
..You could easily make a sector-level copy of a block copy tool.., tell me more about this sorcery?
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| Jul 23, 2014 at 13:45 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 23, 2014 at 13:35 | history | edited | peterh | CC BY-SA 3.0 |
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| Jul 23, 2014 at 13:29 | history | answered | peterh | CC BY-SA 3.0 |