Re: RAID1, a failed disk and performance
On Thursday 27 January 2005 23:12:23, Chad Morland wrote: http://members.chello.at/freebsd-5.3/bonnie-gmirror/summary http://members.chello.at/freebsd-5.3/bonnie-gmirror/detail I expect to see data transfer rate increase when you break the mirror. RAID1 has the higest disk overhead of all RAID configurations and is very inefficient in that regard. It would be interesting to see performance results with the bad disk still attached to the mirror. Unfortunately I am not able to break disks on a whim so I can't test it out. :P I also run the bechmarks with the gnop class invoked. It seems that the 'gnop -f nnn' option doesn't work, so that I couldn't observe any significant performance differences. I own several really nice broken IBM SCSI disks, but they are broken in such a way, that the mirrors break immediately after hitting the damaged areas. Maybe it's the better solution to run smartd from ports/smartctl and replace flaky disks asap. -- Christian Hiris [EMAIL PROTECTED] | OpenPGP KeyID 0x3BCA53BE OpenPGP-Key at hkp://wwwkeys.eu.pgp.net and http://pgp.mit.edu pgpQMiRLIbs6i.pgp Description: PGP signature
RAID1, a failed disk and performance
What happens in terms of performance when a drive in a RAID1 system fails? Will disk access be slower because it attempts to read/write to a failed disk or will performance be faster because it doesn't need to do half the work it usually does? I couldn't really find any online resources that deal with performance levels when there are failed drives present in a RAID array. -CM ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: RAID1, a failed disk and performance
On Thu, Jan 27, 2005 at 03:14:46PM -0500, Chad Morland wrote: What happens in terms of performance when a drive in a RAID1 system fails? Will disk access be slower because it attempts to read/write to a failed disk or will performance be faster because it doesn't need to do half the work it usually does? I couldn't really find any online resources that deal with performance levels when there are failed drives present in a RAID array. I recently set-up and tested a geom-based RAID1. When I pulled a hot-swap SATA drive from the server, I didn't notice any performance degradation. However, I must note that I wasn't running any monitoring software nor gathering empirical data. It's just my observation of the responsiveness of the system while one drive was gone. YMMV. -- Regards, Doug ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: RAID1, a failed disk and performance
On Thursday 27 January 2005 21:14:21, Chad Morland wrote: What happens in terms of performance when a drive in a RAID1 system fails? Will disk access be slower because it attempts to read/write to a failed disk or will performance be faster because it doesn't need to do half the work it usually does? I couldn't really find any online resources that deal with performance levels when there are failed drives present in a RAID array. If you are interested in gmirror software-raid performance, I put some bonnie benchmark data online. I run the benchmark on a cheap none-raid Promise-Ultra-133-TX2 aka PDC20269, which costs about 25 Euros: http://members.chello.at/freebsd-5.3/bonnie-gmirror/summary http://members.chello.at/freebsd-5.3/bonnie-gmirror/detail Cheers, ch -- Christian Hiris [EMAIL PROTECTED] | OpenPGP KeyID 0x3BCA53BE OpenPGP-Key at hkp://wwwkeys.eu.pgp.net and http://pgp.mit.edu pgpGoqCAnqt5g.pgp Description: PGP signature
Re: RAID1, a failed disk and performance
http://members.chello.at/freebsd-5.3/bonnie-gmirror/summary http://members.chello.at/freebsd-5.3/bonnie-gmirror/detail I expect to see data transfer rate increase when you break the mirror. RAID1 has the higest disk overhead of all RAID configurations and is very inefficient in that regard. It would be interesting to see performance results with the bad disk still attached to the mirror. Unfortunately I am not able to break disks on a whim so I can't test it out. :P ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: RAID1, a failed disk and performance
Chad Morland wrote: What happens in terms of performance when a drive in a RAID1 system fails? Will disk access be slower because it attempts to read/write to a failed disk or will performance be faster because it doesn't need to do half the work it usually does? Read access will become slower. Write access will become faster. -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
