On Thu, February 12, 2009 14:02, Tim wrote: > > Right, well I can't imagine it's impossible to write a small app that can > test whether or not drives are honoring correctly by issuing a commit and > immediately reading back to see if it was indeed committed or not. Like a > "zfs test cXtX". Of course, then you can't just blame the hardware > everytime something in zfs breaks ;) >
I can imagine it fairly easily. All you've got to work with is what the drive says about itself, and how fast, and the what we're trying to test is whether it lies. It's often very hard to catch it out on this sort of thing. We need somebody who really understands the command sets available to send to modern drives (which is not me) to provide a test they think would work, and people can argue or try it. My impression, though, is that the people with the expertise are so far consistently saying it's not possible. I think at this point somebody who thinks it's possible needs to do the work to at least propose a specific test, or else we have to give up on the idea. I'm still hoping for at least some kind of qualification procedure involving manual intervention (hence not something that could be embodied in a simple command you just typed), but we're not seeing even this so far. Of course, the other side of this is that, if people "know" that drives have these problems, there must in fact be some way to demonstrate it, or they wouldn't know. -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
