# [OmniOS-discuss] IDE mode and Advanced Format disks

Hugh McIntyre lists at mcintyreweb.com
Sat Sep 14 06:46:46 UTC 2013

- Previous message: [OmniOS-discuss] kvm vnic dhcp disabled, how to enable?
- Next message: [OmniOS-discuss] IDE mode and Advanced Format disks
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

    I have a related question to the recent discussion of ashift=12 and
    advanced format disks.  The problem is that I have 4 disks attached via
    a LSI 9211-4i SATA/SAS adapter (which are fine) but several others
    attached via motherboard SATA connections and running in IDE
    compatibility mode.

    The problem is that in IDE mode, the disks don't report any geometry
    information via format "inq", or "iostat -Er | grep -i vendor", and I
    only get the LSI-attached disks (plus a motherboard attached DVD drive)
    listed from "echo ::sd_state | mdb -k | egrep '(^un|_blocksize)'".

    I'm sure all of these symptoms are linked, i.e. if the kernel does not
    know the disk geometry then iostat and format are not going to report it
    either.  But this seems like a problem for ashift detection logic that
    is not going to be able to get the geometry either.

    (As an aside, no doubt I should have switched from IDE mode long ago ...
    but this is the default :( )

    So my two questions:

    1. If I change the SATA ports to AHCI instead of IDE in the BIOS, I'm
    guessing this will fix the bug, but I also assume this will change the
    paths under /devices and therefore make the system unbootable because
    one of these disks is a SSD containing the rootfs?  Is there a safe way
    to do this, or can I assume the paths will stay the same?  And would I
    get better performance in AHCI mode nowadays?  (This is a
    network-limited backup box so performance is not critical, but one
    partition of the SSD contains L2ARC used for dedup of some of the data).

    2. Is this a bug I should file, with the possbility of being fixed, or
    just a limitation of the IDE layer that will never be able to get disk
    geometries and detect ashift cleanly?

    Thanks,

    Hugh.

    PS: in my case, I worked around this by moving the disks around long
    enough to get the geometry, but a long-term answer would be good.

    > https://www.illumos.org/issues/2665#note-3
    >> http://wiki.illumos.org/display/illumos/ZFS+and+Advanced+Format+disks

- Previous message: [OmniOS-discuss] kvm vnic dhcp disabled, how to enable?
- Next message: [OmniOS-discuss] IDE mode and Advanced Format disks
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

More information about the OmniOS-discuss mailing list