[geeks] bah.

Jonathan C. Patschke jp at celestrion.net
Thu Mar 12 23:45:35 CDT 2009


On Thu, 12 Mar 2009, Phil Stracchino wrote:

>> The geom stuff... it has burned me a lot.  The geom raid software will
>> happily destroy all your data with no warning either from the programs
>> or the man pages, and they frequently locked up FreeBSD 6 and 7.  I
>> have not tried FreeBSD 7.1 yet so things may have improved in that
>> release.
>
> Huh.  I used the recommended geom method for boot disk mirroring ...
> wonder if that was part of the problem?  And considering it was
> mirroring SATA disks, that sounds like a possible double whammy.

Knocking on wood, I have one system that has a pair of geom-mirrored
disks, has seen constant (sometimes very heavy) disk and network activity
since it was turned on 696 days ago, and has absolutely never gone
unavailable.

This system runs FreeBSD 6.2p3 and hasn't spectacular hardware
(entry-level Core 2 Duo CPU, Intel "Classic series" desktop board, Seagate
SATA disks).  It does automated podcast recording and distribution for an
Los Angeles-market radio station.  Outside of icecast segfaulting once, I
don't think it's even gone software-unavailable.  This level of
reliability is why I tout FreeBSD, and this system is largely
representative of how I've seen the OS cope with a constant pounding.

Let me qualify my praise of geom with a stern damning stemming from its
needlessly spartan documentation and overall lack of discoverability.  If
you don't know that it's there (and up until FreeBSD 7 or so, you wouldn't
know unless you asked someone who knew), you won't stumble across it.
And, even if you do stumble across it, the handbook and man pages don't go
into a lot of depth.

For example, the gjournal manpage nowhere tells you that if you have
enough I/O activity to overrun the journal, your box will panic.  That's
the sort of things folks might want to know, just perhaps.

-- 
Jonathan Patschke ( "They don't have the right to read a book out loud."
Elgin, TX         (                  --Paul Aiken
USA               (                    Executive Director, Authors Guild



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