Andre Timmermann wrote: > Good morning. > > Am Dienstag, den 24.06.2008, 02:42 +0200 schrieb Daniel Hokka Zakrisson: > >> > after enabling disklimits, I noticed that starting a guest will > enforce >> > the usage of vdu - this will significantly slow down the start of > the >> > vservers and will even prevent the start, if the guest is over > limits. >> >> Only if you didn't stop the guest cleanly, or if you've just applied > the >> them. vserver ... stop caches the values for vserver ... start. > > OK, I have seen these vdu-processes on machines, which crashed hard. > There was noway to shut down the guests cleanly. And as such, there's no record of how much space the disk consumes, ergo, vdu. >> > I did not find a way to configure this behaviour. I would like to > skip >> > the vdu, as this can be handled later (for example, when you try to >> > enforce such limits on existing customers :) >> >> Huh? And what would you initialize the values to? > > I would prefer to apply them later on the running guest. That's not what I asked. What would you set the current usage to when starting the guest? 0? Some arbitrary value? Also, running vdu on a running guest is racy. It's entirely possible for it to create large files in a directory that has already been processed, leaving you with incorrect values... >> It makes no sense to limit disk usage and say "I don't care about how > much >> it uses." > > On on hand it is a way to limit the guests, on the other hand ist is a > very easy way to monitor the disk usage of the guest. If that's what you're after, you definitely want vdu to run before the guest is started... >> > On some machines the vdu will take up to 90 minutes, which can be > very >> > anoying, if it fails. >> >> "Fails"? How would it "fail"? > > OK, this was not very clear. Lets say, I have a machine with 16 guests. > The machine crashes at night and I have wake up and fix it. If I don't > have to care about vdu, the guest will start within 5 minutes and I can > see if one guest fails to start du to whatever (database, broken > files...) > > If vdu will take two hours to test all guests and a guest fails to > start, I have to wait the whole time to see if all customers are up and > running. I don't know what you're doing to make it take 2 hours... PlanetLab has machines with several hundred guests, and running vdu on all of them as part of the start-procedure. It still takes less than half an hour. > You don't want to share the office with me, when I'm tired ;) > > In addition, the guest which will be startet at last will have a very > long downtime. This may be anoying for that customer, too ;) > >> I don't understand what you're trying to accomplish. Either you want > to >> limit stuff, in which case you _need_ to know how much the current > usage >> is, or you don't, in which case you don't configure it. > > I get your point. It is true, but it seems that I can activate the > limits on a running guest. This will speed up things a lot if something > goes wrong. It is a big difference between a physical limit on a machine > and a handmade virtual limit. I don't have to care about physical > limits, nobody would dare to write files beyond. The problem is just: what do you set the values to? What happens when the guest removes more data than what you set? Calculating usage while the guest is running is, as I said, problematic. You're creating far more serious problems than having to wait a couple of minutes when starting a guest. -- Daniel Hokka Zakrisson