From c72758f33784e5e2a1a4bb9421ef3e6de8f9fcf3 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 22 May 2009 17:17:53 -0400 Subject: block: Export I/O topology for block devices and partitions To support devices with physical block sizes bigger than 512 bytes we need to ensure proper alignment. This patch adds support for exposing I/O topology characteristics as devices are stacked. logical_block_size is the smallest unit the device can address. physical_block_size indicates the smallest I/O the device can write without incurring a read-modify-write penalty. The io_min parameter is the smallest preferred I/O size reported by the device. In many cases this is the same as the physical block size. However, the io_min parameter can be scaled up when stacking (RAID5 chunk size > physical block size). The io_opt characteristic indicates the optimal I/O size reported by the device. This is usually the stripe width for arrays. The alignment_offset parameter indicates the number of bytes the start of the device/partition is offset from the device's natural alignment. Partition tools and MD/DM utilities can use this to pad their offsets so filesystems start on proper boundaries. Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- Documentation/ABI/testing/sysfs-block | 59 +++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 44f52a4..cbbd3e0 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -60,3 +60,62 @@ Description: Indicates whether the block layer should automatically generate checksums for write requests bound for devices that support receiving integrity metadata. + +What: /sys/block//alignment_offset +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a physical block size that is + bigger than the logical block size (for instance a drive + with 4KB physical sectors exposing 512-byte logical + blocks to the operating system). This parameter + indicates how many bytes the beginning of the device is + offset from the disk's natural alignment. + +What: /sys/block///alignment_offset +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a physical block size that is + bigger than the logical block size (for instance a drive + with 4KB physical sectors exposing 512-byte logical + blocks to the operating system). This parameter + indicates how many bytes the beginning of the partition + is offset from the disk's natural alignment. + +What: /sys/block//queue/logical_block_size +Date: May 2009 +Contact: Martin K. Petersen +Description: + This is the smallest unit the storage device can + address. It is typically 512 bytes. + +What: /sys/block//queue/physical_block_size +Date: May 2009 +Contact: Martin K. Petersen +Description: + This is the smallest unit the storage device can write + without resorting to read-modify-write operation. It is + usually the same as the logical block size but may be + bigger. One example is SATA drives with 4KB sectors + that expose a 512-byte logical block size to the + operating system. + +What: /sys/block//queue/minimum_io_size +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a preferred minimum I/O size, + which is the smallest request the device can perform + without incurring a read-modify-write penalty. For disk + drives this is often the physical block size. For RAID + arrays it is often the stripe chunk size. + +What: /sys/block//queue/optimal_io_size +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report an optimal I/O size, which is + the device's preferred unit of receiving I/O. This is + rarely reported for disk drives. For RAID devices it is + usually the stripe width or the internal block size. -- cgit v1.1 From 7fe063268e73681cdca1a6496a25f93d3332f517 Mon Sep 17 00:00:00 2001 From: Andrew Patterson Date: Tue, 2 Jun 2009 14:48:39 +0200 Subject: cciss: add cciss driver sysfs entries Add sysfs entries to the cciss driver needed for the dm/multipath tools. A file for vendor, model, rev, and unique_id is added for each logical drive under directory /sys/bus/pci/devices//ccissX/cXdY. Where X = the controller (or host) number and Y is the logical drive number. A link from /sys/bus/pci/devices//ccissX/cXdY/block:cciss!cXdY to /sys/block/cciss!cXdY/device is also created. A bus is created in /sys/bus/cciss. A link is created from the pci ccissX entry to /sys/bus/cciss/devices/ccissX. Please consider this for inclusion. Signed-off-by: Mike Miller Cc: Stephen M. Cameron Signed-off-by: Jens Axboe --- .../ABI/testing/sysfs-bus-pci-devices-cciss | 33 ++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-pci-devices-cciss (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss new file mode 100644 index 0000000..0a92a7c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-pci-devices-cciss @@ -0,0 +1,33 @@ +Where: /sys/bus/pci/devices//ccissX/cXdY/model +Date: March 2009 +Kernel Version: 2.6.30 +Contact: iss_storagedev@hp.com +Description: Displays the SCSI INQUIRY page 0 model for logical drive + Y of controller X. + +Where: /sys/bus/pci/devices//ccissX/cXdY/rev +Date: March 2009 +Kernel Version: 2.6.30 +Contact: iss_storagedev@hp.com +Description: Displays the SCSI INQUIRY page 0 revision for logical + drive Y of controller X. + +Where: /sys/bus/pci/devices//ccissX/cXdY/unique_id +Date: March 2009 +Kernel Version: 2.6.30 +Contact: iss_storagedev@hp.com +Description: Displays the SCSI INQUIRY page 83 serial number for logical + drive Y of controller X. + +Where: /sys/bus/pci/devices//ccissX/cXdY/vendor +Date: March 2009 +Kernel Version: 2.6.30 +Contact: iss_storagedev@hp.com +Description: Displays the SCSI INQUIRY page 0 vendor for logical drive + Y of controller X. + +Where: /sys/bus/pci/devices//ccissX/cXdY/block:cciss!cXdY +Date: March 2009 +Kernel Version: 2.6.30 +Contact: iss_storagedev@hp.com +Description: A symbolic link to /sys/block/cciss!cXdY -- cgit v1.1