Re: Booting to root on gmirror with disk failure, is it even possible?
Modulok schrieb: Before I invest significantly more time into my current gmirror issues, I have but two simple questions for anyone out there: 1. Has anyone used gmirror for the root partition and been able to successfully boot with one failed (or un-plugged) disk? It's the latter part of the question that is the real issue for me. I'm just looking for a confirmed it's possible. Yes, it is possible. IBM xSeries 346, FreeBSD 6.2-RELEASE, amd64. U360 hard drives. More specs are available from IBM. Using gmirror because we only have an Adaptec HostRAID (aka FakeRAID) controller and not a real ServerRaid, i.e. our SCSI controller basically has no useful RAID capabilities built in. My test case is to unplug any one disk while the system is running. (Don't do this with your system unless your hardware is specified for hot plugging!). FreeBSD detects a bus reset, marks the gmirror as degraded and continues operating normally, and I can also reboot the degraded gmirror without any problems. The more conservative test case is to power down the system, unplug any one disk, and restart the system. No problems with that either. In fact, the absolutely robust behaviour of gmirror was one of my key arguments for switching from Linux to FreeBSD :-). Of course there are a zillion ways to fail your hard disk, and there could be cases where one hard disk might start behaving erratically, and gmirror might not be able to detect all such cases and might try to continue using the failed disk. This could theoretically lead to some nasty data integrity issues in the worst case. But this is true for any RAID, even when implemented in hardware IMO. Regards Tobias -- Universität Stuttgart|Fakultät für Architektur und Stadtplanung|casinoIT 70174 Stuttgart Geschwister-Scholl-Straße 24D T +49 (0)711 121-4228 F +49 (0)711 121-4276 E [EMAIL PROTECTED] I http://www.casino.uni-stuttgart.de ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Booting to root on gmirror with disk failure, is it even possible?
On Sep 4, 2007, at 9:31 PMSep 4, 2007, Modulok wrote: Before I invest significantly more time into my current gmirror issues, I have but two simple questions for anyone out there: 1. Has anyone used gmirror for the root partition and been able to successfully boot with one failed (or un-plugged) disk? It's the latter part of the question that is the real issue for me. I'm just looking for a confirmed it's possible. 2. If yes, what version of FreeBSD, what brand/model of hard disks, and what mainboard was used? We have been using gmirror on some Dell systems for a while now, and we put it through it's paces before we deployed it to production. We pulled drives while the system was running, rebooted, the works. We found gmirror to be pretty fault tolerant and were not able to get it to fail. If you pull your main drive, the system was always able to successfully boot from the second drive. Rebuilding was always possible, as well. Our tests were done on older Dell PowerEdge 1650's with Fujitsu SCSI drives. I don't know specifically what model/manufacturer the motherboard is. If there's any other questions, feel free to ask! - Eric F Crist Secure Computing Networks ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Booting to root on gmirror with disk failure, is it even possible?
1. Has anyone used gmirror for the root partition and been able to successfully boot with one failed (or un-plugged) disk? It's the latter part of the question that is the real issue for me. I'm just looking for a confirmed it's possible. yes it is. but with unplugged, with failed it may not work, depend how disk is failed 2. If yes, what version of FreeBSD, what brand/model of hard disks, and what mainboard was used? any. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
