>>>>> "Wols" == Wols Lists <antlists@xxxxxxxxxxxxxxx> writes: Wols> On 05/10/17 02:26, John Stoffel wrote: >> It's trivial to revert if you know the starting size! And I would argue that the --size option is misnamed, since is is a per-component resize. >> >> In any case, would it be better to print a message which said something like: array md## devices resized from <orig> to <new size> >> Wols> I think a message like "You are setting array space available to Wols> less than array space used. Use --force if you really want to do Wols> this". I think changing the message to say: "Resizing array component size from X to Y." would address a bunch of comments on this thread. And would give people a way to get back to where they were more easily. >> When the user does this? But again, I think the --force option is good to have when reducing the size of component devices, sine I would hope the message gives people a pause and hopefully makes them think. >> Wols> I'm with Neil in that you should never have to use force if Wols> you're doing something sensible. As soon as mdadm says "you need Wols> to use --force" it should be a warning that something is Wols> amiss. So only require it if the array needs the space that Wols> you're reducing away. If you're using 6TB with 3 x 3TB drives, Wols> then reducing component size to 2.1TB shouldn't trigger a Wols> warning ... You're taking both sides of the arguement here! The question in my mind is really if it's *ever* a good idea to reduce the size of components of an array without an explicit command. For growing, sure, that's not a problem. But since we can shrink component (not just the array size!) sizes without warning and destroy people's data, it's upon the tool to at least make some effort to notify them. >> So I really don't think we're holding people back, we're educating them with this warning. >> Wols> Good idea - I just think that the message as you've phrased it Wols> isn't that educative, sorry. That's okay, the message needs to be tweaked for sure. I was just getting out a proof of concept patch. Wols> Looking at your current message, it sounds like you're comparing Wols> current array usage with future array size so that's right - you Wols> just need a warning that sends a clear "you are about to shoot Wols> yourself in the foot" message, not just a "use --force to Wols> suppress this warning". I agree that both A) the message needs to be improved, and B) the --force option needs to be there when you are shrinking. Neil didn't like B as much, but I still think that when shrinkinking, we need to be very hesitant to do something without explicit statement from the user, because it's too easy without the new message (to be done still!) to mess up and break things horribly. As another idea, maybe we could syslog the current device settings before we do any changes, so that there's a log of where you started from and where you ended up? The output of -D might be helpful. Might be noisy... but so what? -- 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
