Date: Sun, 29 Mar 2015 08:24:24 +1000 From: Da Rock <freebsd-fs@herveybayaustralia.com.au> To: Kirk McKusick <mckusick@mckusick.com> Cc: freebsd-fs@freebsd.org Subject: Re: Delete a directory, crash the system Message-ID: <55172A18.70601@herveybayaustralia.com.au> In-Reply-To: <201503282202.t2SM2KAn056827@chez.mckusick.com> References: <201503282202.t2SM2KAn056827@chez.mckusick.com>
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On 03/29/15 08:02, Kirk McKusick wrote: >> Date: Sat, 28 Mar 2015 22:22:26 +1000 >> From: Da Rock <freebsd-fs@herveybayaustralia.com.au> >> To: Kirk McKusick <mckusick@mckusick.com>, Benjamin Kaduk <kaduk@MIT.EDU> >> CC: freebsd-fs@freebsd.org >> Subject: Re: Delete a directory, crash the system >> X-ASK-Info: Message Queued (2015/03/28 05:22:36) >> X-ASK-Info: Confirmed by User (2015/03/28 14:35:33) >> >> On 26/03/2015 03:12, Kirk McKusick wrote: >> >>> The suggestion to disable journalling is a good one. Journalling fixes >>> only consistency errors that it knows about and cannot handle media errors. >>> The sorts of panics you are getting are usually caused by media errors. >>> So disabling journally and checking all metadata after crashes (which is >>> what fsck does) should minimize your problems. >> So my only option for journal is gjournal (slow) or zfs (memory hog) to >> maintain consistency; is that it? Incidentally, why keep SU+J on as >> default then? Wouldn't this be considered a bug still, then? > SU without journaling will maintain consistency. It is just that you > will need to run fsck after a crash. That is the way FFS has been since > it was written in 1982 and will allow you to recover from media errors > which it appears your system is suffering from. SU+J is just a faster > way of restarting but only works when you do not have media errors. I guess the point I'm driving at is that on a server this may be an ok solution, but if you have workstations/desktops with users who don't know how to do this properly, that is why the journalling is an important feature. So its not just about faster restarts, but a simple reboot/boot and everything is basically ok for them. If there is any issue a system squawk at the sysadmin will then allow them to come in at some point to run a proper check. But in this case, we have a system which effectively crashes if there is a problem. So thats why I mentioned the only other journal type fs' in freebsd, because in this scenario a journal is required and it appears these are the only alternative that don't create such a catastrophic effect. Having made my point, what could be done about it - and what can I do to help? Would drive details provide data required to pick up the solution?
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