----- Original Message ----- > From: "David C. Rankin" <drankinatty@xxxxxxxxxxxxxxxxxx> > To: "Linux Raid" <linux-raid@xxxxxxxxxxxxxxx> > Sent: Saturday, 22 August, 2020 03:42:40 > Subject: Re: Feature request: Remove the badblocks list > On 8/18/20 4:03 PM, Håkon Struijk Holmen wrote: >> Hi, >> >> Thanks for the CC, I just managed to get myself subscribed to the list :) >> >> I have gathered some thoughts on the subject as well after reading up on it, >> figuring out the actual header format is, and writing a tool [3] to fix my >> array... >> > <snip> >> But I have some complaints about the thing.. > > Well, > > There is code in all things that can be fixed, but I for one will chime in > and say I don't care if a lose a strip or two so long as on a failed disk I > pop the new one in and it rebuilds without issue (which it does, even when the > disk was replaced due to bad blocks) > > So whatever is done, don't fix what isn't broken and introduce more bugs > along the way. If this is such an immediate problem, then why are patches > being attached to the complaints? The problem is that it's already broken. Take a single mirror. One drive experiences a bad sector, fine, you have redundancy, so you read the data from the other drive and md flags the sector as bad. The drive two is replaced, you lose the data. The new drive will get flagged with the same sector number as faulty, since the first drive has it flagged. So you replace the first drive and during resync, it also gets flagged as having a bad sector. And so on. Modern (that is, disks since 20 years ago or so) reallocate sectors as they wear out. We have redundancy to handle errors, not to pinpoint them on disks and fill up not-so-smart lists with broken sectors that work. If md sees a drive with excessive errors, that drive should be kicked out, marked as dead, but not interfere with the rest of the raid. Vennlig hilsen roy -- Roy Sigurd Karlsbakk (+47) 98013356 http://blogg.karlsbakk.net/ GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt -- Hið góða skaltu í stein höggva, hið illa í snjó rita.
