Hello, Am 03.12.2017 um 18:20 schrieb Phil Turmel: > Very good. At some point you need to replace the desktop drive -- it's > unsafe to use in a raid array -- but it doesn't look like it's blowing > up at the moment. Use the following workaround on every boot until you > replace it: > > echo 180 > /sys/block/sde/device/timeout > > Search the archives for "timeout mismatch" to see many discussions on > why that drive is a time bomb. this is an interesting point. As far as I understand it, there's no difference between a) the device tells the kernel, that an error occurred (ERC) or b) the kernel just waits three minutes. >From my point of understanding, I see no reason to avoid those disks. Just raise this timeout to 180 on all disks. Even those with ERC can be set to 180 seconds, because on some mainboards the order of sdX changes every boot. On your home nas it doesn't really matter if there's an access delay. This is of course not acceptable on enterprise systems. By the way, the kernel doesn't just easily throw the device out. From my experiences it hard resets the link and completely reinitializes the device. Only if that fails, the raid will be degraded and if this fails, the device probably has a problem and should be replaced. I run a raid-6 on six really cheap old second hand 4 TB drives and never had an issue with that in the past two years. I had no real failures and no accidentally or prematurely dropped devices. Mdadm just runs. And this raid writes about 50 GB each and every single day and never goes to sleep. This is what differs mdadm from hardware raid controllers, which really shouldn't used with non ERC drives due to exactly that timing problem. Though I run a check every month, where all data is read, just to make sure it doesn't rot on the discs. In my opinion a (monitored) raid-6 on old, cheap non ERC drives is safer, than a raid-5 on „premium overpriced“ drives. Never forget, it's call raid - random array of inexpensive disks. In cynical words, I see it this way: The hdd and nas manufactures came together and found a way to push the prices up. Regards, Matthias -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
