Re: Have the velociraptors in a test system now, checkout theerrors.

[Justin Piszcz]

On Sun, 14 Dec 2008, Redeeman wrote:

> On Wed, 2008-12-10 at 19:11 -0500, Bill Davidsen wrote:
> > Justin Piszcz wrote:
> > > Point of thread: Two problems, mentioned in detail below, NCQ in Linux
> > > when used in a RAID configuration and two, something with how Linux
> > > interacts with the drives causes lots of problems as when I run the WD
> > > tools on the disks, they do not show any errors.
> > >
> > > If anyone has/would like me to run any debugging/patches/etc on this
> > > system feel free to suggest/send me things to try out.  After I put
> > > the VR's in a test system, I left NCQ enabled and I made a 10 disk
> > > raid5 to see how fast I could get it to fail, I ran bonnie++ shown
> > > below as a disk benchmark/stress test:
> > >
> > > For the next test I will repeat this one but with NCQ disabled, having
> > > NCQ enabled makes it fail very easily.  Then I want to re-run the test
> > > with RAID6.
> > >
> > > bonnie++ -d /r1/test -s 1000G -m p63 -n 16:100000:16:64
> > >
> > > $ df -h
> > > /dev/md3              2.5T  5.5M  2.5T   1% /r1
> > >
> > > And the results?  Two disk "failures" according to md/Linux within a
> > > few hours as shown below:
> > >
> > > Note, the NCQ-related errors are what I talk about all of the time, if
> > > you use
> > > NCQ and Linux in a RAID environment with WD drives, well-- good luck.
> > >
> > > Two-disks failed out of the RAID5 and I currentlty cannot even 'see'
> > > one of the drives with smartctl, will reboot the host and check sde
> > > again.
> > >
> > > After a reboot, it comes up and has no errors, really makes one wonder
> > > where/what the bugs is/are, there are two I can see:
> > > 1. NCQ issue on at least WD drives in Linux in SW md/RAID
> > > 2. Velociraptor/other disks reporting all kinds of sector errors etc,
> > > but when you use the WD 11.x disk tools program and run all of their
> > > tests it says the disks have no problems whatsoever!  The smart
> > > statistics do confirm this.  Currently, TLER is on for all disks, for
> > > the duration of these tests.
> >
> > Just a few comments on this, I have several RAID arrays built on Seagate
> > using NCQ, and yet to have a problem. I have NCQ on with my WD drives,
> > non-RAID, and haven't had an issue with them either. The WDs run a lot
> > cooler than the SG, but they are probably getting less use, as well. If
> > the WD are still on sale after the holiday I may grab a few more and run
> > RAID, by then I will have some small sense of trusting them.
> Velociraptors, or which WD?
Velociraptors or Raptors or 750GiB disks (in Linux SW Raid) the NCQ issue 
does not appear to occur on Raptors on a 3ware card though, only in 
Linux+SW_raid.  The regular raptor/750gib also run just fine as standalone 
with NCQ.

Justin.
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