Disabling write cache for SCSI and native mode SATA disks may not be
necessary. Flushes/write barriers may be honored at the protocol layer
more reliably, thus allowing a journaled filesystem to do its work.
On Thu, 2006-02-23 at 11:06 -0800, Christian Rice wrote:
> Perhaps no one else is using XFS as a root filesystem on SATA drives,
> but I've been giving it a go. And I've been lucky to NOT experience a
> power failure in my machine room, I guess.
>
> I've tried blktool and sdparm, both RPMS and compiled locally, but
> nothing can turn off the write cache. I'm using multiple motherboards,
> different drive manufactureres, but no avail.
>
> Has anyone had success with this issue? Am I forced to continue on with
> PATA drives for the foreseeable future?
>
> Any informed responses would be a huge help.
>
>
> Details:
> Tyan mobo, Opteron, 2.6.12-1.1398_FC4smp, x86_64, WDC WD800JD-00LS SATA
> drive
> modules:
> sata_sil 15301 4
> libata 58825 1 sata_sil
> sd_mod 25153 6
> scsi_mod 167417 2 libata,sd_mod
>
>
> nForce4 mobo, Athlon64 X2, 2.6.15-1.1831_FC4smp, x86_64, ST380817AS SATA
> drive
> modules:
> libata 98265 1 sata_nv
> sd_mod 53697 2
> scsi_mod 195321 2 libata,sd_mod
>
>
>
> Christian Rice wrote:
>
> > We all know that disabling write cache on drives with no battery
> > backup is a good thing, and we all know how to do it on your average
> > IDE drive (hdparm -W0 /dev/hda).
> >
> > But what about on SATA disks? I've found sdparm, which has settings
> > for disabling write cache on SCSI disks (and supposedly SATA disks
> > that use the SCSI device (eg, /dev/sda). It simply doesn't work, though:
> >
> > [root@sqld xian]# sdparm --set WCE=1 /dev/sda
> > /dev/sda: ATA Maxtor 7Y250M0 YAR5
> > change_mode_page: failed setting page: Caching (SBC)
> >
> > [root@sqld xian]# uname -r
> > 2.6.14-1.1656_FC4smp
> >
> > Of course I'm using XFS...
> >
> > The sdparm web page suggests some SCSI commands will be better
> > implemented in kernel 2.6.15.
> >
> > The only other thing I might try here is to recompile a 64-bit version
> > of sdparm, as I downloaded/installed version .96 i386, but this system
> > is a dual-proc Opteron running 64-bit FC4.
> >
> > Anyone have any other ideas?
> >
> >
> >
> >
>
> On Mon, Jan 30, 2006 at 12:19:51PM -0800, Christian Rice wrote:
>
> >> We all know that disabling write cache on drives with no battery backup
> >> is a good thing, and we all know how to do it on your average IDE drive
> >> (hdparm -W0 /dev/hda).
> >>
> >> But what about on SATA disks?
> >
> >
>
> Is blktool the New(tm) way to do this?
>
> -- Russell Howe | Why be just another cog in the machine,
> rhowe@xxxxxxxxxxxx | when you can be the spanner in the works?
>
>
>
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