Date: Fri, 06 May 2011 11:33:26 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Sergey Kandaurov <pluknet@gmail.com> Cc: FreeBSD-Current <freebsd-current@freebsd.org> Subject: Re: Switch from legacy ata(4) to CAM-based ATA Message-ID: <4DC3B256.8050800@FreeBSD.org> In-Reply-To: <BANLkTinDLPybTLJ6z0Zdds9n_nQerJ8%2B1Q@mail.gmail.com> References: <4DAEAE1B.70207@FreeBSD.org> <BANLkTinDLPybTLJ6z0Zdds9n_nQerJ8%2B1Q@mail.gmail.com>
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Sergey Kandaurov wrote: > XENHVM uses it's own naming scheme and can name disks as daN or adN, > depending on virtual block device id. atapci0/ata0/ata1 devices still present > there (such as in Bruce Cran's dmesg), but no any disks attached from it: > instead, all of them hung from device/vbd/N. > [In a non-XENHVM mode they are attached from ataN channels, as usual.] > > /* > * Translate Linux major/minor to an appropriate name and unit > * number. For HVM guests, this allows us to use the same drive names > * with blkfront as the emulated drives, easing transition slightly. > */ > > xenbusb_front0: <Xen Frontend Devices> on xenstore0 > xenbusb_back0: <Xen Backend Devices> on xenstore0 > xctrl0: <Xen Control Device> on xenstore0 > xbd0: 17000MB <Virtual Block Device> at device/vbd/768 on xenbusb_front0 > xbd0: attaching as ad0 > GEOM: ad0s1: geometry does not match label (16h,63s != 255h,63s). > xbd1: 3812MB <Virtual Block Device> at device/vbd/2048 on xenbusb_front0 > xbd1: attaching as da0 > xbd2: 114439MB <Virtual Block Device> at device/vbd/2064 on xenbusb_front0 > xbd2: attaching as da1 OK, interesting question. I have built amd64 XENHVM kernel and booted it under Xen 3.2. As result I've got double set of devices, via both atapci0/ata0 and via blkfront: ada0 at ata0 bus 0 scbus0 target 0 lun 0 ada0: <QEMU HARDDISK 0.9.0> ATA-7 device ada0: Serial Number QM00001 ada0: 16.700MB/s transfers (WDMA2, PIO 8192bytes) ada0: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C) ada0: Previously was known as ad0 ada1 at ata0 bus 0 scbus0 target 1 lun 0 ada1: <QEMU HARDDISK 0.9.0> ATA-7 device ada1: Serial Number QM00002 ada1: 16.700MB/s transfers (WDMA2, PIO 8192bytes) ada1: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C) ada1: Previously was known as ad1 xbd0: 476940MB <Virtual Block Device> at device/vbd/768 on xenbusb_front0 xbd0: attaching as ad0 xbd1: 476940MB <Virtual Block Device> at device/vbd/832 on xenbusb_front0 xbd1: attaching as ad1 Both of them were exported to GEOM. Extra set of adX devices caused error messages. What am I doing wrong and why have I got those duplicates? Was I required to remove non-PV drivers from my kernel? > Probably, /sys/dev/xen/blkfront/blkfront.c needs updating by s/"ad"/"ada"/g; > or such. I believe, xen generates sequential numbers starting from zero > (or rather such numbers that can be converted to sequential numbers), > similar to what ATA_CAM does. According to what I see, blkfront follows ATA_STATIC_ID behavior: if I configure Xen with single slave device (hdb), blkfront reports it as ad1. -- Alexander Motin
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