Bug#606968: DMA: Out of SW-IOMMU space with Xen kernel during heavy I/O
On Tue, 14 Dec 2010, Rik Theys wrote:
On Tue, 14 Dec 2010, Ben Hutchings wrote:
On Tue, 2010-12-14 at 13:24 +0100, Rik Theys wrote:
This system _has_
a RAID controller and the disk is in a RAID1. Why would the filesystem
switch
to read-only mode? Is it because the RAID is too slow? If the RAID is too
slow,
this should just give a high iowait, but not make the file system
read-only?
The DMA mapping failure will be treated as an I/O error. Most
filesystems do not attempt to retry after an error. This has nothing to
do with the speed of the disk.
Since you use RAID, the failure may only put a single disk in degraded
state, which will then be recoverable in the usual way. The error would
be hidden from the filesystem.
The RAID in this system is a PERC H200, which should be a hardware RAID card.
Can the mpt2sas driver see the physical disks that are part of the RAID?
Looking at the kernel messages from bootup, the mpt2sas driver does seem to know
about the individual disks.
There's also a failure message:
[ 29.201218] mpt2sas0: failure at /build/buildd-linux-2.6_2.6.32-29-amd64-xcs37n/linux-2.6-2.6.32/debian/build/source_amd64_xen/drivers/scsi/mpt2sas/mpt2sas_scsih.c:3801/_scsih_add_device()!
Is this message harmless?
Regards,
Rik
[ 27.279835] mpt2sas0: Allocated physical memory: size(739 kB)
[ 27.279838] mpt2sas0: Current Controller Queue Depth(467), Max Controller Queue Depth(3439)
[ 27.279840] mpt2sas0: Scatter Gather Elements per IO(128)
[ 27.519864] mpt2sas0: LSISAS2008: FWVersion(02.15.63.00), ChipRevision(0x03), BiosVersion(07.01.09.00)
[ 27.519869] mpt2sas0: Dell PERC H200 Integrated: Vendor(0x1000), Device(0x0072), SSVID(0x1028), SSDID(0x1F1E)
[ 27.519873] mpt2sas0: Protocol=(Initiator,Target), Capabilities=(Raid,TLR,EEDP,Snapshot Buffer,Diag Trace Buffer,Task Set Full,NCQ)
[ 27.519949] mpt2sas0: sending port enable !!
[ 29.200976] mpt2sas0: host_add: handle(0x0001), sas_addr(0x5842b2b07007cf00), phys(8)
[ 29.201218] mpt2sas0: failure at /build/buildd-linux-2.6_2.6.32-29-amd64-xcs37n/linux-2.6-2.6.32/debian/build/source_amd64_xen/drivers/scsi/mpt2sas/mpt2sas_scsih.c:3801/_scsih_add_device()!
[ 34.448533] mpt2sas0: port enable: SUCCESS
[ 34.448775] scsi 0:1:0:0: Direct-Access Dell Virtual Disk 1028 PQ: 0 ANSI: 6
[ 34.449083] scsi 0:1:0:0: RAID1: handle(0x004f), wwid(0x033ce95f5ae26e63), pd_count(2), type(SATA)
[ 34.449092] scsi 0:1:0:0: qdepth(128), tagged(1), simple(1), ordered(0), scsi_level(7), cmd_que(1)
[ 34.449315] scsi 0:1:0:0: Attached scsi generic sg1 type 0
[ 34.451378] scsi 0:0:0:0: Direct-Access ATA WDC WD1602ABKS-1 3B05 PQ: 0 ANSI: 5
[ 34.451586] scsi 0:0:0:0: SATA: handle(0x000a), sas_addr(0x4433221106000000), device_name(0x4ee1500110f80366)
[ 34.451590] scsi 0:0:0:0: SATA: enclosure_logical_id(0x5842b2b07007cf00), slot(1)
[ 34.451674] scsi 0:0:0:0: atapi(n), ncq(y), asyn_notify(n), smart(y), fua(y), sw_preserve(y)
[ 34.451677] scsi 0:0:0:0: qdepth(32), tagged(1), simple(1), ordered(0), scsi_level(6), cmd_que(1)
[ 34.451873] scsi 0:0:0:0: Attached scsi generic sg2 type 0
[ 34.453956] scsi 0:0:1:0: Direct-Access ATA WDC WD1602ABKS-1 3B05 PQ: 0 ANSI: 5
[ 34.454165] scsi 0:0:1:0: SATA: handle(0x000b), sas_addr(0x4433221107000000), device_name(0x4ee150010cda0366)
[ 34.454169] scsi 0:0:1:0: SATA: enclosure_logical_id(0x5842b2b07007cf00), slot(0)
[ 34.454253] scsi 0:0:1:0: atapi(n), ncq(y), asyn_notify(n), smart(y), fua(y), sw_preserve(y)
[ 34.454256] scsi 0:0:1:0: qdepth(32), tagged(1), simple(1), ordered(0), scsi_level(6), cmd_que(1)
[ 34.454455] scsi 0:0:1:0: Attached scsi generic sg3 type 0
[ 34.460429] sd 0:1:0:0: [sda] 311427072 512-byte logical blocks: (159 GB/148 GiB)
[ 34.460542] sd 0:1:0:0: [sda] Write Protect is off
[ 34.460546] sd 0:1:0:0: [sda] Mode Sense: 03 00 00 08
[ 34.460614] sd 0:1:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[ 34.460873] sda: sda1 sda2 sda3
[ 34.466279] sd 0:1:0:0: [sda] Attached SCSI disk
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