3 ms·
You're placing a lot of trust in you presumably consumer-level disks. Even if the filesystem is perfectly crash-tolerant under some specific model of disk behav
by ambrop7 11y ago
You're placing a lot of trust in you presumably consumer-level disks. Even if the filesystem is perfectly crash-tolerant under some specific model of disk behavior, the disk could always behave outside of that model, especially upon sudden loss of power.
Story: some time ago, I tried to hook up an SATA hard disk into a desktop PC which had an SSD connected, while the machine was running. When I did so, I got errors in dmesg about the SSD failing and being reset automatically. I rebooted and grub took ~30s to load the kernel then the boot hanged in the middle.
Luckily after some power cycling the issue was gone but I honestly taught I lost the SSD. Apparently disks don't like losing power. Possibly this was even worse because it was just a temporary voltage drop (the disks were connected to the same supply cable).
- javajosh 11y agoIs SATA designed to allow hot plugin of a hard drive? That would surprise me.
- ambrop7 11y agoAs far as I know, it is an optional feature that both the controller and the drive have to support, to use reliably.
- dogma1138 11y agoAnd it then needs to be explicitly requested which usually means bypassing the cache to avoid any delayed writes. But even then hotswap was never meant to ensure data consistency it just allows the controller to reinitialize new disks without a full reset.
- digi_owl 11y agoDo wonder if you would have seen that issue if it was another SSD. Thing about spinning platters is that it takes a fair bit of initial juice to get them spinning. Thats why some USB HDDs come with y cables to get those few extra miliamps from the second port.