Re: UNEXPECTED SOFTUPDATES INCONSISTENCY
Gabriel Ambuehl wrote: Hello Heinrich, Sunday, February 22, 2004, 5:00:27 PM, you wrote: Why that? I can imagine that i lose data in case of a power failure, but why in case of a crash? Well I guess the card COULD still commit the data, however, who knows if it actually does it? And why is write cache only dangerous with softupdates, as you wrote above? IIRC softupdates relies on the assumption that when the softupdate changes return, they really ARE on the disk. It's the same with most RDBMS: because they go to great lengths to ensure the journal is in an ok state they need to know for sure that the data they wrote to it actually made it to disk. Since i found no word about disabling write cache in the FreeBSD handbook or in man tuning(7), i would really like to know, if this is just a rumour, or where does it come from? I can't say for sure, but I have little confidence in write caching anyhow. It changes semantics the system relies on, for one. Best regards, Gabriel Gabriel, what you write does make sense, although i really can't understand why this important info is not in the FreeBSD documentation. I have disabled write cache, but i will keep softupdates disabled as well for now, and see how the system behaves. Thanks for your help, Heinrich ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: UNEXPECTED SOFTUPDATES INCONSISTENCY
Gabriel Ambuehl wrote: Hi Heinrich Rebehn, you wrote. Make sure you've disabled write caching on the drive firmware itself... HR> Does this also apply for RAID disks (twe)? Also, there is no word about HR> this in man tuning(7). Is this more of a guess or is softupdates HR> definately dangerous with wite cache enabled? I'd say it's the other way round: write cache is dangerous with softupdates. Softupdates itself is certainly better than no softupdates, even if it takes a slight performance drop by disabling write cache. I think you should disable the write cache on the 3ware cache (not sure whether there actually is one, mine don't come with any RAM sockets) anyway as you'll lose all data in there in the event of a crash. Why that? I can imagine that i lose data in case of a power failure, but why in case of a crash? And why is write cache only dangerous with softupdates, as you wrote above? I had always write cache enabled on my twe controller, but my problems with softupdates definetely started with 5.2 Since i found no word about disabling write cache in the FreeBSD handbook or in man tuning(7), i would really like to know, if this is just a rumour, or where does it come from? Regards, Gabriel Heinrich Rebehn University of Bremen Physics / Electrical and Electronics Engineering - Department of Telecommunications - Phone : +49/421/218-4664 Fax :-3341 ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: UNEXPECTED SOFTUPDATES INCONSISTENCY
Lowell Gilbert wrote: Heinrich Rebehn <[EMAIL PROTECTED]> writes: I have had the above error 2 times now during fsck after an unclean shutdown. fsck -y yielded tons of entries in lost+found. man (7) tuning says that softupdates guarantees filesystem consistency in case of crash, but thousands of lost files tell a different story. Did i miss anything? Or should i disable softupdates for important data? Make sure you've disabled write caching on the drive firmware itself... Does this also apply for RAID disks (twe)? Also, there is no word about this in man tuning(7). Is this more of a guess or is softupdates definately dangerous with wite cache enabled? I have also used softupdates with 4.9 and did not get these errors. The system is running FreeBSD 5.2.1-RC2 I hope you have read the Early Adopter's Guide: http://www.freebsd.org/releases/5.2R/early-adopter.html Yes i have and after asking others on this list, got the impression that 5.2 is usable for the most common hardware and applications. But now i am seriously considering going back to 4.9 Thanks very much for your reply :-) Heinrich ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: UNEXPECTED SOFTUPDATES INCONSISTENCY
Heinrich Rebehn <[EMAIL PROTECTED]> writes: > I have had the above error 2 times now during fsck after an unclean > shutdown. fsck -y yielded tons of entries in lost+found. > man (7) tuning says that softupdates guarantees filesystem consistency > in case of crash, but thousands of lost files tell a different story. > Did i miss anything? Or should i disable softupdates for important data? Make sure you've disabled write caching on the drive firmware itself... > The system is running FreeBSD 5.2.1-RC2 I hope you have read the Early Adopter's Guide: http://www.freebsd.org/releases/5.2R/early-adopter.html ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
