Differences between disk controllers

[Pokala, Ravi]

>Date: Mon, 10 Mar 2014 22:52:16 +0100
>From: Willem Jan Withagen <wjw at digiware.nl>
>To: hardware at freebsd.org
>Subject: Differences between disk controllers
>Message-ID: <531E3410.5090602 at digiware.nl>
>Content-Type: text/plain; charset=ISO-8859-1
>
>Hi,
>
>Running:
>	FreeBSD 10.0-STABLE #0 r262730
>
>I've build a ZFS system, with 4 disks on a regular Marvell controller,
>and 4 disks on an Areca controller. Disk are 4T WD REDs.
>
>I noticed that there were some discrepancies when I build a raidz of 4
>"marvell" disks when compared to a raidz on the Areca controller.
>
>The essential difference is that on the basic controller the disks are
>recognised as being 4K disks with quirks. On the Areca controller there
>is no quirk that matches...
>
>Is this a typical problem on the Areca controller? Or does this not work?

The Marvell controller is recognized as a SATA controller, so the drives
attached to it are treated as SATA drives, using the ATACAM stack:

    ada0: <WDC WD40EFRX-68WT0N0 80.00A80> ATA-9 SATA 3.x device


The drive in question is listed along with the SATA quirks:


    sys/cam/ata/ata_da.c :: ada_quirk_table[]
        {
                /* WDC Caviar Green Advanced Format (4k) drives */
                { T_DIRECT, SIP_MEDIA_FIXED, "*", "WDC WD????RX*", "*" },
                /*quirks*/ADA_Q_4K
        },


The Areca controller appears to be acting as a *SAS* controller, so the
drives attached to it are treated as SAS drives, using the SCSICAM stack:

    da0: <WDC WD40EFRX-68WT0N0 R001> Fixed Direct Access SCSI-5 device

While the SCSICAM stack knows about quirks for SCSI/SAS drives, it doesn't
know anything about quirks for SATA drives.

There may be an argument there to create a unified quirk list, but that's
a larger discussion.

-Ravi

>Thanx,
>--WjW
>
>Basic:
>mvs0: <Marvell 88SX7042 SATA controller> port 0xb800-0xb8ff mem
>0xfcd00000-0xfcdfffff irq 16 at device 0.0 on pci4
>mvs0: Gen-IIe, 4 3Gbps ports, Port Multiplier supported with FBS ioapic0:
>routing intpin 16 (PCI IRQ 16) to lapic 0 vector 53
>
>With disk:
>ada0 at mvsch0 bus 0 scbus1 target 0 lun 0
>ada0: <WDC WD40EFRX-68WT0N0 80.00A80> ATA-9 SATA 3.x device
>ada0: Serial Number WD-WCC4E0918074
>ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
>ada0: Command Queueing enabled
>ada0: 3815447MB (7814037168 512 byte sectors: 16H 63S/T 16383C)
>ada0: quirks=0x1<4K>
>
>And:
>arcmsr0: <Areca SATA 3G Host Adapter RAID Controller (RAID6 capable)
>arcmsr version 1.20.00.28 2013-09-13> mem
>0xfcbff000-0xfcbfffff,0xfb800000-0xfbbfffff irq 18 at device 14.0 on pci3
>Areca RAID adapter0: ARC-1220 F/W version V1.49 2010-12-02
>
>With disk:
>da0 at arcmsr0 bus 0 scbus0 target 0 lun 0
>da0: <WDC WD40EFRX-68WT0N0 R001> Fixed Direct Access SCSI-5 device
>da0: Serial Number WD-WCC4E0959610
>da0: 250.000MB/s transfers (125.000MHz, offset 32, 16bit)
>da0: Command Queueing enabled
>da0: 3815447MB (7814037168 512 byte sectors: 255H 63S/T 486401C)
>da0: Delete methods: <NONE(*)>