Date: Mon, 19 Mar 2007 08:52:15 -0700 From: "Steve Franks" <stevefranks@ieee.org> To: "Toomas Aas" <toomas.aas@raad.tartu.ee> Cc: questions@freebsd.org Subject: Re: Converting from ata-raid to gmirror Message-ID: <539c60b90703190852s70e2170di49b92de4a41b8e4f@mail.gmail.com> In-Reply-To: <45FDAA18.1080203@raad.tartu.ee> References: <45BFB6A1.9080200@raad.tartu.ee> <45FDAA18.1080203@raad.tartu.ee>
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On 3/18/07, Toomas Aas <toomas.aas@raad.tartu.ee> wrote: > On January 30th, I wrote: > > > I'm currently running FreeBSD 6.2-RELEASE (amd64) on a system based on > > Intel SE7230NH1-E motherboard, which has Intel ICH7R integrated > > softraid. The machine has two 500 GB drives which are configured as > > RAID1 in BIOS. Unfortunately, this setup seems to have some stability > > issues which I can't figure out how to solve. Specifically, when the > > storage subsystem is put under heavy load (such as doing nightly > > backups) the kernel starts spitting out horrible error messages such as: > > > > FAILURE - out of memory in ata_raid_init_request > > g_vfs_done():ar0s1f[WRITE(offset=8091172864, length=16384)]error = 5 > > FAIg_vfs_done():ar0LURE - out of memsory in ata_raid_1init_reqfu[eWsRItTE(o > > ffset=8091F1A8I9LU2R4E8 ,- oleuntg tohf= 16m3e8m4o)ry]e rirno ra t=a 5 > > _raid_init_requestg > > vfs_done():ar0s1f[WRITE(offsFAeItL=UR8E0 9-1 2o05u6t3 2o,f > > lmeengmtoh=ry1 6i3n8 4a)t]ae_rrraoird _=in i5t > > > > If it looks like garbage, then yes, this is how it appears in > > /var/log/messages. I'm seriously afraid that similar corruption is > > sneaking into important user files. > > > > Only thing I can think of is converting this setup from BIOS-based RAID > > to gmirror. This would involve, I think, modifying /etc/fstab so that it > > references ad4 instead of ar0, then permanently breaking the mirror in > > BIOS, booting up the system with single disk and then basically > > following the gmirror chapter in the handbook. Correct? > > > > I'm also a little uncertain about "permanently breaking the mirror" > > part. I've read all the motherboard and LSI docs I can find and this > > topic isn't covered anywhere. > > Well, finally I could summon up enough courage to perform this procedure > on a production server (such as it is). To break the mirror, I just went > to motherboard BIOS (not the BIOS-based RAID utility) and changed the > 'Configure SATA as' setting from 'RAID' to 'IDE'. Generally everything > seems to have gone OK. The system now runs from /dev/mirror/gm0, which > consists of ad4 and ad6. However, the kernel still sees the old ar0 > array and complains that it's broken. Do I care, or should I just remove > 'device ataraid' from kernel configuration? > > kernel: ar0: WARNING - mirror protection lost. RAID1 array in DEGRADED mode > kernel: ar0: 476772MB <LSILogic v3 MegaRAID RAID1> status: DEGRADED > kernel: ar0: disk0 READY (master) using ad4 at ata2-master > kernel: ar0: disk1 DOWN no device found for this subdisk > > -- > Toomas > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" > I'm just getting into this myself as well, but from previous people who've helped me, I've come to understand that most motherboard 'raid' controllers are not tru hardware raid, just a fancy wrapper around software raid, and they do pretty much exactly the same thing as gmirror - write a special metadata tag near the end of the disk with the info on the mirror. This is what ataraid sees that causes it to find 'ar0' - delete that metadata from the disk, and ar0 will go away. Possibly there is an extra slice with a couple of blocks at the end of the disk? That's about the extent of my knowledge... Steve
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