zfs hang in zio->io_cv) with dd read

[Goran Lowkrantz]

--On October 7, 2010 17:50:42 +0200 John Hay <jhay at meraka.org.za> wrote:

> On Thu, Oct 07, 2010 at 02:35:31PM +0200, Ivan Voras wrote:
>> On 10/07/10 14:15, John Hay wrote:
>> > Hi,
>> >
>> > I got hold of a SunFire X4500 with 48 X 500G disks and thought to try
>> > FreeBSD 8-stable with zfs on it.
>> >
>> > I have setup the two boot disks in a zfs mirror and then the rest in
>> > a pool of 6 X raidz2 of 7 disks each.
>> >
>> > I have created a 10G file with dd in the second pool, but if I try to
>> > read it with dd, dd will hang in "zio->io_cv)" according to ^T. This
>> > happens everytime. The first time I saw messages about an interrupt
>> > storm, so I have put "hw.intr_storm_threshold=10000" in
>> > /etc/sysctl.conf. According to "systat -vm 1" there is atapci for 2-3
>> > seconds and then it is quiet.
>>
>> There are two things you could try: 1) use the AHCI driver
>> (ahci_load="YES" in /boot/loader.conf) and 2) disable superpages, they
>> don't get along on a few models of Opterons (vm.pmap.pg_ps_enabled=0 in
>> /boot/loader.conf).
>
> ahci does not grab them. According to the ahci man page, it can handle
> Marvell 88SX61xx, while these are MV88SX6081 according to pciconf -lcv:
>
> atapci0 at pci0:1:1:0:     class=0x010000 card=0x11ab11ab chip=0x608111ab
> rev=0x09 hdr=0x00     vendor     = 'Marvell Semiconductor (Was: Galileo
> Technology Ltd)'     device     = 'MV88SX6081 8-port SATA II PCI-X
> Controller'
>     class      = mass storage
>     subclass   = SCSI
>     cap 01[40] = powerspec 2  supports D0 D3  current D0
>     cap 05[50] = MSI supports 1 message, 64 bit
>     cap 07[60] = PCI-X 64-bit supports 133MHz, 512 burst read, 4 split
> transactions

Then try mvs_load="YES"

mvs0 at pci0:6:2:0:	class=0x010000 card=0x11ab11ab chip=0x608111ab rev=0x09 
hdr=0x00
    vendor     = 'Marvell Semiconductor (Was: Galileo Technology Ltd)'
    device     = 'MV88SX6081 8-port SATA II PCI-X Controller'
    class      = mass storage
    subclass   = SCSI
mvs1 at pci0:5:1:0:	class=0x010000 card=0x11ab11ab chip=0x608111ab rev=0x09 
hdr=0x00
    vendor     = 'Marvell Semiconductor (Was: Galileo Technology Ltd)'
    device     = 'MV88SX6081 8-port SATA II PCI-X Controller'
    class      = mass storage
    subclass   = SCSI

>
> I have also set vm.pmap.pg_ps_enabled=0 in loader.conf, but that did not
> make a difference either. :-(
>
> Once dd hang in that "zio->io_cv)" state the rest of the machine is ok
> and everything works as long as you stay away from the directory where
> the file is that you dd from.
>
> There are no messages in dmesg or /var/log/messages.
>
> John
> --
> John Hay -- jhay at meraka.csir.co.za / jhay at FreeBSD.org
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/glz