[OmniOS-discuss] puzzlingly slow disk access

[Michael Mounteney]

On Mon, 31 Dec 2012 12:14:28 -0500
Eric Sproul <esproul at omniti.com> wrote:

> Michael,
> The SATA ports on this system appear to be operating in
> legacy/compatible/IDE mode (note the lack of a "t" section in, e.g.
> c3d0s0).  Disk performance in this mode is pretty poor.  It would be
> preferable to have the SATA ports in native/AHCI mode, but in the case of
> the rpool that will change the device names and leave you with an
> unbootable system.  You can 1) backup and restore your system after
> switching the SATA mode to native/AHCI, 2) just do a fresh reinstall after
> switching modes or 3) attempt to fix up the various places where the device
> paths are embedded (these paths are what change when the mode changes).
>  For #3, see
> http://mail.opensolaris.org/pipermail/zfs-discuss/2011-July/049175.html for
> hints.

Thanks Eric,

I did (2) and it made dd copy 4.3 times faster (9.6 MB/s --> 43 MB/s) but curiously VirtualBox machines don't seem that much fasster.  But thanks for the advice, which did what I asked-for.

At the weekend I'll try my X4200 which copies at 70 MB/s, on SAS disks.

-- 
_________________
Michael Mounteney