Date: Mon, 9 Nov 2015 20:55:11 +0000 From: Steven Hartland <steven@multiplay.co.uk> To: Tim Gustafson <tjg@ucsc.edu> Cc: "freebsd-fs@freebsd.org" <freebsd-fs@freebsd.org> Subject: Re: ZFS RAID 0+1 Throwing Checksum Errors Message-ID: <-7786625913476013857@unknownmsgid> In-Reply-To: <CAPyBAS7oYvp6vvzetcGmrXy0_Qn0fXBN_d510w41CguDZCzMxw@mail.gmail.com> References: <CAPyBAS7oYvp6vvzetcGmrXy0_Qn0fXBN_d510w41CguDZCzMxw@mail.gmail.com>
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I would check for bad memory or cabling. If you have a hot swap midplane and the disks are linked at 6gbps that could also be the issue. In short it's more likely to be a hardware issue than software > On 9 Nov 2015, at 19:09, Tim Gustafson <tjg@ucsc.edu> wrote: > > I have a FreeBSD 10.1 server configured as root-on-zfs with the > following pool configuration: > > NAME STATE READ WRITE CKSUM > tank ONLINE 0 0 0 > mirror-0 ONLINE 0 0 0 > gpt/zfs0 ONLINE 0 0 0 > gpt/zfs1 ONLINE 0 0 0 > mirror-1 ONLINE 0 0 0 > gpt/zfs2 ONLINE 0 0 0 > gpt/zfs3 ONLINE 0 0 0 > > The disks are each 1TB Samsung 850EVO SSDs connected via an mrsas Dell > Perc raid controller configured in "RAID Disabled" mode. > > I run a "zpool scrub" every weekend and every weekend the scrub finds > a handful (usually between 1 and 10) checksum errors per disk. The > scrub fixes the checksum errors, and I clear the counters and > everything seems fine. As far as I know, I do not have any corrupt or > missing data. > > The server is a fairly busy web and database server, handling about 5 > million hits per day. > > I'm wondering if the problem is that the scrub is calculating the > checksum for the data on gpt/zfs0, and while that's happening, some > data is updated by Apache or MySQL, and then checksum for the data on > gpt/zfs1 is calculated, which now doesn't match, and therefore the > scrub is reporting an error. Is that possible? > > If that's not it, could this be a bug? Or should I be worried about > my SSDs? What additional data would be helpful for me to share to > diagnose this? > > -- > > Tim Gustafson > Technical Lead, Baskin School of Engineering > tjg@ucsc.edu > 831-459-5354 > Baskin Engineering, Room 313A > _______________________________________________ > freebsd-fs@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
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