Messages in this thread |  | | | Date | Fri, 3 Apr 2009 09:33:49 +0200 | | From | Pavel Machek <> | | Subject | Re: Ext4 and the "30 second window of death" |
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> If you are a mail client developer, and the user says, "I want the > advantages of IMAP, but I refuse to switch to an ISP that provides > IMAP; you must give me *all* the advantages IMAP even though I'm using > POP3", you'd probably tell the user, "Yes, and do you want a pony, > too?"
Somebody wants a pony?
> The problem is, this is what the application programmers are telling > the filesystem developers. They refuse to change their programs; and > the features they want are sometimes mutually contradictory, or at > least result in a overconstrained problem --- and then they throw the > whole mess at the filesystem developers' feet and say, "you fix it!" > > I'm not saying the filesystems are blameless, but give us a little > slack, guys; we NEED some help from the application developers here.
From what I seen on the gtk lists, application developers are willing to change they code. _But_ we should make sure that it does not regress. fsync() is a regression: spins the disk up too much, slow on ext3. (They may be willing to do that, but I believe that's a very bad idea). And yes, I hope your "lets add fsync() everywhere, then break the fsync with eat-my-data-^W-laptop-mode" plan does not happen. (Please acknowledge that it is a stupid idea...)
If you give them fbarrier() or replace() or something that is nop or nearly so on ext3 data=ordered and fixes ext4/btrfs, they'll happily use it. But we do not have such thing now, and we should not be really asking them to regress on existing setups. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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