Date: Wed, 19 Nov 2008 10:58:29 -0800 From: Jeremy Chadwick <koitsu@FreeBSD.org> To: John Almberg <jalmberg@identry.com> Cc: freebsd-questions@freebsd.org Subject: Re: snmpd strangeness Message-ID: <20081119185829.GA4786@icarus.home.lan> In-Reply-To: <A0526D15-3EF3-40E3-9362-F80DE5FF364C@identry.com> References: <BFDB04F6-6032-4CBE-859A-CB2BEE3A4C4E@identry.com> <20081119164919.GA2347@icarus.home.lan> <EFB2D630-CDB6-4E5C-98BF-5A37A3502D71@identry.com> <20081119172649.GA3139@icarus.home.lan> <A0526D15-3EF3-40E3-9362-F80DE5FF364C@identry.com>
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On Wed, Nov 19, 2008 at 12:34:55PM -0500, John Almberg wrote: >>> Now I'm curious about snmp, so perhaps I'll try to figure out how to >>> get >>> it to something useful. This machine has 8 hard drives, and is >>> located in >>> Manhattan, so I would certainly like to be informed if one of the >>> raid >>> drives went on the blink. That was one of the things he was trying >>> to get >>> working. >> >> Net-SNMP won't give you the status of the RAID. Neither will bsnmpd >> (10. >> FreeBSD simply does not have the hooks to make this possible. Someone >> needs to write the code. I do not recommend relying on shell scripts >> tied into Net-SNMP to accomplish this either (for a lot of very good >> reasons); write the code in native C. >> >> It also greatly depends on what you're using for RAID. If a hardware >> controller, good luck getting the status out of an API natively (sans >> Areca, which I believe offers an API) -- you'll resort to shell >> scripts >> and CLI binaries, in which case you're *easily* better off with a >> cronjob, periodic(8), or a log monitor daemon. > > This machine has an Intel motherboard and a hardware raid controller. > From what I can tell, there is some Intel software installed on the > machine that makes hardware faults visible to snmp. That would require Net-SNMP to be linked to that software (or library) directly. Two things can't just "magically talk" to one another. :-) AFAIK, Intel does not provide such software on FreeBSD, but I could be complete wrong here. They primarily focus on Linux, like most companies do. > That last sentence makes it sound like I know more than I do about this > situation. I'm just reading from notes. :-) > > And I have an Intel disk that came with the motherboard that hints at > the same type of thing. I've just scanned the docs on the disk... looks > extraordinarily complicated. I don't know what controller it is, but Net-SNMP doesn't have any sort of out-of-the-box support for any kind of RAID card. See above for what's needed. I just hope the card is an actual RAID card and not BIOS-level RAID like Intel MatrixRAID. If it is MatrixRAID, I highly recommend you back the entire machine up and reinstall without MatrixRAID, otherwise when you lose a disk or need to rebuild your array, you'll find your array broken/gone, be completely unable to rebuild it, or kernel panics. Note that all of this stuff works just fine on Linux; the issues listed are with FreeBSD. Generally speaking, we (the open-source world) have gotten to the point with OS-based software RAID (e.g. Linux LVM, FreeBSD ccd/gvinum/ZFS, OpenSolaris ZFS) where it offers significant advantages over hardware RAID. There are good reasons to use hardware RAID, but in those scenarios admins should be looking at buying an actual filer, e.g. Network Appliance. Otherwise, for "simple" systems (even stuff like 2U or 3U boxes with many disks, e.g. a "low-cost filer"), stick with some form of OS-based software RAID if possible. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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